Is Iminify really free?

Yes. Every level, every format, resizing and the page scanner are free, with no watermark and nothing to pay. A guest can compress 10 images a day, each up to 16 MB and 64 megapixels. A free account raises that to 40 a day, opens the page scanner and keeps your history with your account for as long as you have one, across devices and browsers.

How do I compress an image without losing quality?

Choose Lossless. For a JPEG, PNG or GIF it repacks the file without re-encoding a single pixel, so the image you get back is identical to the one you uploaded, only smaller. A lossy WebP has no repack step, so it is re-encoded at the highest quality the level allows, and a HEIC or TIFF always comes back in another format. If you can accept changes you can't see, Smart shrinks files much further while aiming to keep every image at 40 dB PSNR or better against your upload.

What is the difference between Lossless, Smart and Ultra?

Lossless changes no pixels in a JPEG, PNG or GIF. Smart searches for the lowest quality that still reaches 40 dB PSNR against the original, which is below the threshold people notice, then checks the result on a perceptual scale (SSIMULACRA 2) so a mostly flat picture isn't let through at a quality its detail doesn't deserve. Ultra runs the same search with a 34 dB target and a lower perceptual bar, so files get smaller and fine texture softens slightly. The search covers images up to 36 megapixels and the perceptual check up to 8. Anything larger, and a busy photo that can't reach the target even at the level's quality ceiling, is encoded at that ceiling. None applies your resize or format choice and compresses nothing.

Which format gives the smallest file: JPG, PNG, WebP or AVIF?

It depends on the image and on the level, which is why Auto exists. On the ten samples on this page, AVIF gave the smallest file at Smart and Ultra on nine of them, often by half: the food photo is 44 KB as AVIF against 60 KB as WebP at Smart, and the social card 11 KB against 34 KB. The one exception is the desktop screenshot, where a quantised PNG beat everything. Ask for Lossless and the order flips: WebP's lossless mode won nine of ten, because AVIF has no efficient lossless path. Auto encodes every format that can hold your image and keeps the smallest, so you don't have to guess.

Should I convert my images to WebP?

For anything served on a website, yes. WebP is supported by every current browser, keeps transparency and animation, and is typically far smaller than a JPEG or PNG of the same picture. Keep a JPG or PNG only for places that can't read WebP, such as older desktop software or some email clients.

Can I compress HEIC photos from an iPhone?

Yes. Upload the HEIC as it is and pick a format under Format, because browsers don't display HEIC and Iminify doesn't write it. WebP or JPG are the usual choices. Turn on Keep EXIF under Metadata if you want the capture date and location to stay in the file. The photo comes out the right way up, whichever way you held the phone.

Does compressing remove EXIF and location data?

By default, yes. Camera model, exposure settings and GPS coordinates are all stripped, which is what you want for anything published. Turn on Keep EXIF to carry the metadata across, including into WebP and AVIF. Orientation is applied to the pixels before the tag goes, so a stripped photo never comes back sideways, and a Display P3 or CMYK profile is converted to sRGB rather than thrown away.

Is there a file size or image count limit?

Each image can be up to 16 MB as a guest and 32 MB with a free account, and 64 megapixels either way. You can drop a whole batch at once. Guests can compress 10 images a day and a free account 40; the count resets 24 hours after your first image. Very long file names are shortened before upload so they don't get rejected.

Can I compress animated GIFs?

Yes, and every frame is kept. Lossless runs gifsicle's lossless optimiser. Smart and Ultra apply gifsicle's lossy mode as well, which took a 44-frame test animation down by 27% and 42% respectively. Converting an animated GIF to WebP keeps the animation and usually shrinks it further, and resizing an animation keeps every frame too.

Can I resize and compress at the same time?

Yes, and it's the better way to do it. The resize writes a lossless intermediate and the compressor encodes that once, so you pay for a single lossy generation. Resizing in one tool and compressing in another costs you two.

Why is my optimised file the same size as the original?

Because nothing beat it. If no encoder produced a smaller file than your upload, you get your own bytes back and the result is marked Already Optimized. This is common for images that were already compressed hard, such as JPEGs saved from another website. Ultra or a format change usually still finds savings: set it on the page and pick Recompress from the row's menu.

Can I compress every image on my website at once?

Yes. Open the page scanner and paste a page URL. Iminify opens the page in a browser, collects every image it loads, compresses each one with your settings and packages them into one zip for you to upload back.

Can I see what the compression changed?

Yes, on every result. Press the Compare button on the row for the original and the optimized copy on one drag-to-compare stage, side by side, or as a difference map that colours each pixel by how much it moved and reports the share that changed noticeably and the PSNR. The map is computed in your browser from the two files, so nothing is uploaded again. It is switched off for a resized result, whose pixels no longer line up with the original's, and a HEIC or TIFF original your browser can't draw is shown as the optimized copy alone.

Can I run the same image again with different settings?

Yes. Change the level, the format or the size on the page, then pick Recompress in the row's menu. The new result is encoded from the original you uploaded, never from the optimized copy, so you don't stack one generation of loss on another. The first result stays until you delete it, and a re-run counts as one of your daily images.

Can Iminify write alt text for my images?

Yes, it does by default. Each image you compress gets a one-sentence description for its alt attribute, so screen readers and search engines know what it shows, and a suggested file name. Click the ALT badge beside a result to copy the text or use the name. Pick the language under Alt text above the upload box, turn on Rename files to have every download take the suggested name, or switch it off. The text is written by AI, so read it before you publish it.

Can I share a result with someone?

Yes. Share in the row's menu tells you first that the image becomes public and only creates the link when you agree. The link is 24 random characters, isn't listed anywhere and asks search engines to stay away. Anyone who opens it sees the optimized copy, the original, the compare views and both downloads, and can run the original through their own settings without signing in. Stop sharing switches the link off, and deleting the image ends it too. A guest can switch it off while the browser session lasts, about two hours, and after that by emailing us the link.

Compress Images Online Free: JPG, PNG, WebP, AVIF

Before and after

See it on real images before you upload yours

These 10 images went through the exact pipeline your upload goes through, with every level and every format, and nothing was tuned by hand. Drag the handle, put the two side by side, or switch to Difference and see every pixel that moved, with the PSNR. Then change the level and the format and read the numbers off the results.

Best result so far: 97.2% smaller, Ultra level, AVIF.

All 10 samples at Smart, same format: 3.89 MB in, 1.45 MB out, 62.7% smaller overall.

Fjord, from a camera

Rock, water and sky at 1800 by 1200, saved the way a camera saves it: quality 92, full chroma. Fine texture everywhere, which is where lossy encoders spend their bytes.

Level

Output format

Compare

Original · ·

Optimized

Drag to compare

Original

Optimized

Comparing every pixel

The difference couldn't be computed in this browser.

Same Changed

Brighter means a bigger change. Over 40 dB is hard to tell apart by eye; under 30 dB shows at a glance.

Look the same? Good, that's the job. And no, we didn't put the same picture on both sides: the only difference you're supposed to see is the file size.

The map and its numbers are computed in your browser from the two files on screen, the way the compare view on a result of your own does it. Smart aims at 40 dB and Ultra at 34 when it writes a JPG, WebP or AVIF, then holds the result to a perceptual score as well (70 for Smart and 50 for Ultra on the SSIMULACRA 2 scale, which the map can't show), and a result under its PSNR target stopped at the level's quality ceiling rather than grow the file; a PNG is quantised to fewer colours instead, with no target. Lossless comes out identical except where a file has to be re-encoded, a JPEG converted to another format or a lossy WebP, and there it gets the level's top quality.

Original

Optimized

Every result for this image

	Same format	WebP	AVIF
Lossless
Smart
Ultra

Try it with your own images

What Iminify does

One upload, four jobs, one download

Most image tools do one thing and make you chain three sites together for the rest. Iminify compresses, converts, resizes and strips or keeps metadata in a single pass, so your image is re-encoded once and only once. Two encodes in a row cost you quality twice. One doesn't.

Compress, with the quality chosen per image

A fixed quality setting treats a foggy sky and a brick wall the same, and they aren't. Smart encodes each image at several qualities, measures how far each one drifted from your upload, and keeps the smallest that still clears a 40 dB PSNR target. It then scores that file on the SSIMULACRA 2 scale, which is built to match what people see, and sends the search back up when it lands under 70. Ultra does the same with a 34 dB target and a bar of 50.

Convert to WebP, AVIF, PNG or JPG

Pick a format, or pick Auto and let the encoders compete. Up to about eight megapixels, Auto writes every format your image can be saved in without losing transparency or animation and hands you whichever came out smallest; above that it goes straight to WebP, the format that wins most often. You never pay for a conversion that made the file bigger.

Resize by pixels or by percent

Set a width, a height, or both, or scale the whole image down to a percentage. Resizing uses a Lanczos filter and writes a lossless intermediate, so the format encoder is still the only step that loses anything.

Or compress a whole page at once

Paste a URL and the page scanner finds every image the page loads, runs each one through this same compressor with your settings, and gives you one zip. Built for the moment you inherit a site full of 4 MB hero images. It comes with a free account.

Scan a page instead

Metadata is stripped by default, camera model and GPS location included. Flip Keep EXIF on and it rides along, even into AVIF, where most tools quietly drop it. Stripping never leaves a phone photo on its side: the orientation tag is applied to the pixels before it goes, and a Display P3 or CMYK colour profile is converted to sRGB instead of just dropped, so the colours stay put.

Compression levels

What each level actually promises

Other compressors give you a slider from 1 to 100 and leave you guessing, though quality 80 in one encoder isn't quality 80 in another. Iminify's levels are defined by measurements, not a number: how far the compressed pixels are allowed to drift from yours, in decibels of peak signal-to-noise ratio, and how different the result is allowed to look on the SSIMULACRA 2 scale, a score built to match what people see. Higher is closer to the original on both. Above roughly 40 dB the difference isn't visible at normal size, and above 70 on the second scale it's hard to fault without the original next to it.

Level	What it promises	What happens	Pick it when
Lossless	Not one pixel changes in a JPEG, PNG or GIF	The file is repacked, never re-encoded. JPEGs get an optimised Huffman table and progressive scan, PNGs a tighter deflate pass, GIFs a lossless gifsicle run. A lossy WebP has no repack step, so it is re-encoded at the highest quality the level allows. A sideways phone JPEG is rotated losslessly on the way through and keeps its colour profile. The one exception to the promise is a PNG or WebP tagged with a wide-gamut profile such as Display P3: its colours are converted to sRGB, so the values change but the picture doesn't.	Logos, line art, anything you'll edit again, or when the file is evidence.
Smart	No visible change, targets 40 dB PSNR and a perceptual score of 70	A quality search runs per image and stops at the lowest quality that still clears the PSNR target. That answer is then scored on the SSIMULACRA 2 scale, because an average over every pixel lets a mostly flat picture through at a quality its detail doesn't deserve, and when it falls under 70 the search moves back up until it doesn't. Photos and graphics end up at different qualities because they need different ones; an image that cannot reach the targets inside the quality ceiling is encoded at the ceiling.	Almost everything on a website. This is the default for a reason.
Ultra	Smallest file, targets 34 dB PSNR and a perceptual score of 50	The same two-stage search with lower targets. Fine texture softens a little; edges and text stay sharp.	Thumbnails, backgrounds, email images, anything shown small or blurred anyway.
None	No compression at all	Only the resize, conversion or metadata setting you chose is applied. Without a resize or a conversion every pixel comes back as it was: the file only loses its metadata, and with Keep EXIF on it comes back byte for byte.	You only wanted to resize or convert, and quality is someone else's decision.

One honest caveat. A JPEG or WebP you upload has already lost something. A "lossless" pass can only repack a JPEG, and a lossy WebP has no repack step at all, so Lossless re-encodes it at the highest quality the level allows; a Smart pass measures drift against the file you gave us, not the photo it came from. That is why a heavily compressed web JPEG barely shrinks: there's little left to remove. A photo straight off a phone or camera shrinks a lot. And one about size: the quality search runs on images up to 36 megapixels and the perceptual check on images up to 8. Past those the level's quality ceiling decides, so a very large photo is compressed at a fixed setting instead of a measured one.

Formats

Which format should you pick?

You can upload PNG, JPG, JPEG, WEBP, GIF, HEIC, HEIF, TIFF, TIF. You can get back WebP, AVIF, PNG or JPG. Here's when each one is the right answer, and when to let Auto decide.

Format	Best for	Transparency	Animation	Worth knowing
WebP	The default for the web. Photos, graphics, screenshots.	Yes	Yes	Supported by every current browser. Iminify encodes it with cwebp at its slowest, most thorough setting, and losslessly for PNG sources when you ask for Lossless.
AVIF	Photos and graphics for current browsers. The smallest file on nine of the ten samples above.	Yes	No	The newest format and the slowest to encode. Smart and Ultra search each image for the lowest AVIF quality that still clears the level's PSNR floor, the same floor every other format is held to, and at that floor AVIF beat WebP and JPG on every photograph and graphic above. Only the desktop screenshot went to PNG. Lossless is where it struggles: AVIF's lossless mode came out bigger than WebP's on nine of ten. Supported in Chrome, Firefox, Edge and Safari 16.4 or newer.
JPG	Photos that have to open anywhere, including old software.	No	No	Encoded with jpegli, the JPEG encoder from the JPEG XL project: adaptive quantisation and a psychovisual model inside a standard JPEG that opens anywhere. On thirteen test photographs it came in 4.7% under mozjpeg at Smart with better perceptual scores, in a third of the time. Lossless repacks use mozjpeg's jpegtran. Progressive by default.
PNG	Logos, icons, UI, anything with hard edges or transparency that must open everywhere.	Yes	No	Smart and Ultra quantise to a palette of at most 256 colours with pngquant, which is where the big PNG savings come from. Small and mid-sized PNGs then get a zopfli deflate pass at every level, which packed the lossless test files 3 to 16 points tighter than optipng; very large ones get optipng instead, because zopfli is priced per pixel. Lossless keeps every colour.
GIF	Short animations where WebP isn't an option.	Yes	Yes	Every frame is kept. Convert an animated GIF to WebP and the animation survives too; convert it to PNG, JPG or AVIF and only the first frame does.
HEIC	Uploading iPhone photos. Output as JPG, WebP or AVIF.	No	No	Input only. Browsers don't display HEIC, so the useful move is HEIC in, WebP or JPG out.

Not sure? Choose Auto. For images up to about eight megapixels it encodes every candidate format and keeps the smallest; bigger ones go straight to WebP. In the showcase above, AVIF takes nine of the ten samples at Smart and the desktop screenshot goes to PNG, while Lossless hands nine of ten to WebP. The right answer depends on the picture and the level, which is exactly why a fixed choice leaves bytes on the table.

Popular conversions

How it works

Three steps, no sign-up

1
Pick a level and, if you like, a format or size

Smart is selected for you. Use Format to convert, Size to scale and Metadata to keep EXIF.
2
Drop your images

A whole batch at once, up to 16 MB each as a guest and 32 MB with a free account. Each one is queued the moment it lands and starts compressing on our servers.
3
Download one file or all of them

Every result shows the original size, the new size and the saving. Compare any of them with its original, rename what needs a new name, then tick the ones you want and download a single zip.

After the result

Check it, tune it, name it, pass it on

A result is a row with Compare and Download buttons and a menu for the rest. Most tools stop at the download button. Everything on the row works on the original we already have, so nothing is uploaded twice, and none of it needs an account.

Compare it with the original, three ways

Compare puts the two on the drag-to-compare stage from the showcase above, side by side, or on a difference map: every pixel coloured by how far it moved, with the share that changed noticeably and the PSNR in decibels. That is the measurement the levels promise, computed in your browser from the two files, so a Smart result can be checked against its 40 dB target before you trust it.

Compress it again with other settings

Not small enough, or a touch too soft? Change the level, the format or the size on the page and pick Recompress. The new result is encoded from the original you uploaded, never from the optimized copy, so a second pass does not stack a second generation of loss on the first. Both results stay in the list until you delete one, and a re-run counts as one of your daily images.

Rename it before you download

Give a result the name it will have on your site, or select a batch and number them in one go. The single download, the zip and the preview all use the new name, and the extension follows the format you chose.

Share it on a page of its own

Share gives a result a public page: the optimized copy, the original, the three compare views and both downloads, plus a button that lets whoever opens it run the same original through their own settings. The link is 24 random characters nobody can guess, nothing lists it, search engines are asked to stay out, and Stop sharing switches it off. Nothing is public until you press Share and agree.

For AI assistants

Or ask Claude, ChatGPT or Cursor to do it

Iminify has an MCP server, so an AI app can compress, convert and resize images and optimize whole pages on your account. Tell it what you want; it brings back the links.

How it works Setup guide

"Make every image on my homepage lighter"
"Convert these PNGs to AVIF"
"Resize to 1200 wide and strip EXIF"

Guest, account or Pro

Compress without an account, sign up for more, or go Pro and forget the caps

No trial and no card to start. A guest gets 10 images a day and a history that lives in this browser. A free account raises that to 40, opens the page scanner and keeps your history with your account for as long as you have one. Pro takes the daily caps away, raises the size limit to 90 MB and puts your uploads ahead of the queue, from $3 a month.

What you get	Guest Drop a file, get it back. Nothing to fill in.	Free account Free forever One form and one email to verify, and the limits move.	Pro No daily caps $3 a month billed $36 a year, 40% less than monthly $5 a month billed month to month, cancelled any time For the days when 40 images are not enough.
Images a day	10	40	Unlimited
AI alt texts a day	10	40	Unlimited
Page scans a day	Not included	3	Unlimited
Images per scan	Not included	20	150
File size	16 MB	32 MB	90 MB
Queue	Standard	Fast	Fastest
Uploads a minute	10	20	60
History	In this browser	In your account	In your account
All levels and formats	Included	Included	Included
Smart quality per image	Included	Included	Included
Auto format	Included	Included	Included
Format conversions	Unlimited	Unlimited	Unlimited
Resize, convert, keep EXIF	Included	Included	Included
Batch upload, one zip	Included	Included	Included
Compare, recompress, rename and share	Included	Included	Included
Share page reports, CSV and PDF	Not included	Not included	Included
API	Not included	Included	Included
AI agents (MCP server)	Not included	Included	Included
Webhooks	Not included	Not included	Included
Watermarks and ads	None	None	None
	Start without an account	Create a free account	Go Pro

The daily counts reset 24 hours after your first image. Signing up takes a name, an email and a password, or one click with Google, GitHub, Microsoft or Apple, and the account stays free. Pro is paid by card, PayPal, Apple Pay or Google Pay, renews on its own and can be cancelled any time from your plan page. Payment methods and billing questions are on the pricing page.

Your images

Straight answers about where your files go

Uploads travel over an encrypted connection and are compressed on servers we run ourselves, never by a third-party API. The encoders are jpegli, mozjpeg's jpegtran, pngquant, zopfli, optipng, cwebp, gif2webp, avifenc and gifsicle, running on our own machines. AI alt text is different: unless you switch it off above the upload box, a small copy of each image goes to Anthropic, whose Claude model describes it. Anthropic doesn't train on it and deletes it within 30 days, unless its safety systems flag it or the law requires it to be kept longer.

We keep your originals and your optimised copies rather than deleting them on a timer, so a result is still there when you come back for it.

A free account isn't required to compress. Sign up and your history stays with your account instead of this browser, for as long as you have one, so every result is still there on another device or after your cookies are gone, and the daily allowance goes from 10 images to 40.

Nothing you upload is public. A result gets a public page only when you press Share and agree, at an address of 24 random characters that nothing lists and that search engines are asked not to index, and Stop sharing takes it down again.

Questions

Questions people ask before they upload

From the blog

What we've measured so far

We run the encoders on real photos and screenshots and publish the numbers: when WebP beats AVIF, what quality 80 means in each encoder, and how many kilobytes an image on a web page should weigh.

All posts

Two white cards on a blue gradient: WebP at quality 75, 35.1 KB, score 68.0, and AVIF at quality 47, 25.5 KB, score 68.8, beside the headline "A quality of 75 ships as WebP 75, or AVIF 47 if enabled".

What image quality does Next.js ship? WebP 75, AVIF 47 if you list it, and by default a 90 becomes 75

We built a Next.js 16.4.3 app with four images on one page, two of them declared with quality={90} and quality={100}. All 36 image addresses in the page's HTML said q=75. We also asked the image endpoint for q=90 directly, and it answered HTTP 400: "q" parameter (quality) of 90 is not allowed. That is Next 16's default: the list of allowed qualities is [75], and the component moves anything else to the nearest entry. This post follows the 75 to the encoder, in WebP and in AVIF if you switch it on, across 867 requests to a self-hosted /_next/image on nine source images. The default WebP puts one of our five photographs at 1080 px above 70, the "high quality" mark on SSIMULACRA 2, a perceptual score. AVIF at the same setting was 36.5 percent smaller across our 27 image and width combinations, and more than 3 points below WebP on score in 8 of them.

Oct 27, 2026 7 min read

Two enlarged crops of the same red text saved as JPEG at quality 80, one at 4:2:0 and one at 4:4:4, beside the title. The 4:2:0 crop has a duller, browner red.

Why is red text blurry in JPG and WebP? Chroma subsampling, measured

On a test page we made full of red text, no quality from 30 to 100 lifted a plain 4:2:0 encode (no -sharp_yuv) past 58.2 on the SSIMULACRA 2 scale, which runs to 100: JPEG (cjpegli) reached 57.9, WebP 55.2, AVIF (avifenc) 58.2. The same JPEG written at 4:4:4 scored 81.6 at quality 90. That gap is chroma subsampling: 4:2:0 keeps colour at a quarter of the detail that brightness gets, and 4:4:4 keeps all of it. It's why red text looks blurry in a JPG or a WebP. The fix is 4:4:4 for JPEG and AVIF, -sharp_yuv for lossy WebP (which narrows the gap), or lossless WebP on a flat page; What we'd use has the numbers and commands.

Oct 26, 2026 6 min read

Bar chart of the saving range for each kind of JPEG: camera and AI originals 8.6 to 16.3 percent, editor exports 5.1 to 9.4, web-sized files 2.4 to 7.7, and an Iminify Smart output 0.0.

JPEG

How much does lossless JPEG compression save? 25 files, every pixel checked

Lossless JPEG compression with mozjpeg's jpegtran -copy none took between 0 and 16.3 percent off the 25 JPEGs we tested. Together they shrank 9.5 percent, from 164.1 MB to 148.5 MB, and the median file lost 6.6 percent. Every one still decodes to the same pixels. Where a file lands depends on where it came from. Camera and AI originals saved 8.6 to 16.3 percent, files exported from an editor 5.1 to 9.4, and thumbnails and sample photos sized for the web 2.4 to 7.7. The one file that Iminify's Smart level had already compressed, the Smart file below, saved nothing. Cloudflare's documentation says its lossless mode saves 21 percent on average "compared to unoptimized image files", with no figure for JPEG alone (page updated 21 April 2026). We didn't run it, and the best of ours saved 16.3.

Oct 23, 2026 8 min read

Your first image takes about ten seconds

Scroll up, drop a file, watch the size fall. If it doesn't shrink, you'll get your original back and nothing lost.

Compress an image now Scan a whole page

See it on real images before you upload yours

Fjord, from a camera

One upload, four jobs, one download

Compress, with the quality chosen per image

Convert to WebP, AVIF, PNG or JPG

Resize by pixels or by percent

Or compress a whole page at once

What each level actually promises

Which format should you pick?

Popular conversions

Three steps, no sign-up

Pick a level and, if you like, a format or size

Drop your images

Download one file or all of them

Check it, tune it, name it, pass it on

Compare it with the original, three ways

Compress it again with other settings

Rename it before you download

Share it on a page of its own

Or ask Claude, ChatGPT or Cursor to do it

Compress without an account, sign up for more, or go Pro and forget the caps

Straight answers about where your files go

Questions people ask before they upload

What we've measured so far

What image quality does Next.js ship? WebP 75, AVIF 47 if you list it, and by default a 90 becomes 75

Why is red text blurry in JPG and WebP? Chroma subsampling, measured

How much does lossless JPEG compression save? 25 files, every pixel checked

Your first image takes about ten seconds