Is this image compressor free, and are my images private?

Yes, it is completely free with no limits on how many images you compress. It also runs entirely in your browser: your images are decoded and re-encoded on your own machine and are never uploaded to a server. Signing in is only required to download your results, so your work can follow you across our other tools. Because nothing is uploaded, it is safe to use on confidential or client images.

Will compressing an image reduce its quality?

Lossy compression removes detail, but at sensible settings the detail it removes is the detail your eye does not register, so the result looks identical to the original at a fraction of the size. That is exactly why the tool puts a before and after slider at its centre: you can look directly at each image and confirm the quality held before you download it, rather than trusting a number.

What is the difference between WebP, JPEG and PNG?

JPEG is a lossy format built for photographs, small and universally supported but with no transparency. PNG is lossless and built for flat graphics, logos and screenshots with sharp edges and transparency, but it is a poor and heavy choice for photos. WebP is the modern all-rounder: it compresses better than both, supports transparency like PNG, and is supported by every current browser, which is why Auto converts to it.

Can I compress several images at once?

Yes. Add up to thirty images at a time, tune the quality and format once, and every image is re-encoded with those settings. You can then download them individually or grab the whole set as a single zip file, which the tool builds in your browser.

Why did an image come out the same size, or larger?

Some images are already efficiently compressed, and re-encoding them only adds format overhead, so the result can match or even exceed the original. When that happens the tool keeps your original file untouched and tells you, so what you download is always the smaller of the two. If you want a genuinely smaller file from an already-optimised image, lowering the quality or converting the format is usually what does it.

Does compressing images help my website's SEO?

Yes, indirectly but meaningfully. Images are usually the heaviest part of a page, and lighter images make the page load faster, which improves your Core Web Vitals, in particular Largest Contentful Paint. Google uses page speed as a ranking signal and a faster page also keeps visitors from leaving, so compressing and serving images in a modern format is one of the highest-impact performance fixes available.

Free Tool

Free Image Compressor, smaller files, same quality

Drop in a batch of images and shrink them all with a single quality slider, right here in your browser. Compare the before and after side by side to confirm the quality held, convert to modern WebP in a click, and download one file or the whole set as a zip. Nothing is uploaded, so even a folder of client photos never leaves your machine.

Images are the single heaviest thing on most web pages, and an uncompressed one is dead weight. A photo straight off a phone or a camera can be four or five megabytes, and a screenshot saved as a PNG is often larger still, so a page with a handful of them can weigh more than the entire rest of the site put together. That weight is not free: it slows the page down, it drags your Largest Contentful Paint into the red in PageSpeed, it burns through a visitor's mobile data, and Google treats the slowness as a ranking signal. The frustrating part is that almost none of that weight is doing any work. The same image, re-encoded at a sensible quality or converted to a modern format, routinely comes out sixty to eighty percent smaller with no visible difference at all. The catch with most compressors is that you cannot see whether the quality survived until after you have downloaded the file, and many of them upload your images to a server you know nothing about to do the work. This tool fixes both: you watch the quality hold on a before and after slider before you commit, and every image is processed on your own machine.

What image compression actually does

Compression makes an image file smaller by storing it more cleverly, and it comes in two kinds. Lossless compression, which is what PNG uses, rewrites the exact same pixels in a more compact form, so nothing is thrown away but the savings are modest. Lossy compression, which is what JPEG and WebP use, throws away detail the human eye barely registers, which is how it reaches savings of seventy percent and beyond. The quality slider is the dial between the two extremes: at ninety it discards almost nothing, at forty it discards a lot. The reason a lower quality is usually safe is that the first detail to go is the detail you were never going to notice, subtle gradients and fine noise, long before anything you actually look at starts to degrade. That is why a photo at quality seventy-five is, to the eye, identical to the original at a fraction of the size.

Why the format matters as much as the quality

The single biggest saving is often not the quality slider at all, it is the format. WebP, supported by every current browser, typically produces files twenty-five to thirty-five percent smaller than a JPEG at the same visible quality, and far smaller than a PNG for anything photographic, while still supporting transparency. A screenshot or a photo saved as a PNG is the classic mistake: PNG is lossless and built for flat graphics and sharp edges, so forcing a photograph through it produces a huge file for no benefit. Converting that same image to WebP or JPEG can cut it by ninety percent. This tool defaults to Auto, which encodes to WebP, because for the overwhelming majority of images that is the right answer. When you need a specific format for compatibility, for an email signature or an older system, you can force JPEG or PNG instead.

See the result before you trust it

The problem with every quality slider is that a number is not a promise. Quality seventy means nothing until you can see what it did to this particular image, because a flat graphic and a detailed photograph degrade completely differently at the same setting. So the centre of this tool is a before and after comparison: drag the handle across each image and the original is on one side, the compressed version on the other, aligned pixel for pixel, so you can look straight at the areas that matter and confirm the quality held before you download anything. The tool also protects you from the compressor's most annoying failure, handing back a file that is actually bigger than the one you started with. That happens when an image is already efficiently compressed and re-encoding it only adds overhead. When it does, the tool keeps your original untouched and tells you why, so what you download is never worse than what you dropped in.

How to use it

1
Add your images
Drag images straight onto the tool or click to choose them. Add up to thirty at once, in PNG, JPEG, WebP, GIF, BMP or AVIF. Every file is decoded and compressed in your browser, so nothing is uploaded and even sensitive images stay on your machine.
2
Set the quality and format
Drag the quality slider to trade size against fidelity; seventy to eighty is indistinguishable from the original for most photos. Leave the format on Auto to convert to modern WebP, or force JPEG or PNG when you need a specific format for compatibility.
3
Compare before and after
Click any image to open it in the comparison viewer, then drag the handle to reveal the original on one side and the compressed version on the other. Check the detail that matters to you and confirm the quality held before you commit to it.
4
Download one or all
Download a single image, or download the whole batch as one zip file. Exporting asks you to sign in with a free account, which is the only thing an account is needed for; compressing and comparing are always free and never require one.

Common mistakes

Saving photographs as PNG

PNG is lossless and made for flat graphics, logos and screenshots with sharp edges, not for photographs. A photo saved as a PNG can be ten times larger than it needs to be. Convert it to WebP or JPEG and the same image, at the same visible quality, shrinks dramatically.

Pushing the quality far lower than you need

The savings from quality flatten out fast. Dropping from ninety to seventy usually removes most of the file size with no visible change, but dropping from seventy to forty adds little further saving while introducing blocky artefacts. Use the comparison slider to find the point just before the quality visibly breaks, and stop there.

Converting a transparent image to JPEG

JPEG has no transparency, so a logo or icon with a transparent background comes out with a solid white box behind it. Keep transparency by choosing WebP, which compresses well and supports an alpha channel, and reserve JPEG for photographs that have no transparency to lose.

Serving one huge image to every device

Compression makes a file lighter, but a two thousand pixel wide image is still overkill for a phone showing it four hundred pixels wide. Compress the file here, and also serve appropriately sized versions with responsive image markup so a small screen never downloads a desktop-sized image.

Questions

Is this image compressor free, and are my images private?: Yes, it is completely free with no limits on how many images you compress. It also runs entirely in your browser: your images are decoded and re-encoded on your own machine and are never uploaded to a server. Signing in is only required to download your results, so your work can follow you across our other tools. Because nothing is uploaded, it is safe to use on confidential or client images.
Will compressing an image reduce its quality?: Lossy compression removes detail, but at sensible settings the detail it removes is the detail your eye does not register, so the result looks identical to the original at a fraction of the size. That is exactly why the tool puts a before and after slider at its centre: you can look directly at each image and confirm the quality held before you download it, rather than trusting a number.
What is the difference between WebP, JPEG and PNG?: JPEG is a lossy format built for photographs, small and universally supported but with no transparency. PNG is lossless and built for flat graphics, logos and screenshots with sharp edges and transparency, but it is a poor and heavy choice for photos. WebP is the modern all-rounder: it compresses better than both, supports transparency like PNG, and is supported by every current browser, which is why Auto converts to it.
Can I compress several images at once?: Yes. Add up to thirty images at a time, tune the quality and format once, and every image is re-encoded with those settings. You can then download them individually or grab the whole set as a single zip file, which the tool builds in your browser.
Why did an image come out the same size, or larger?: Some images are already efficiently compressed, and re-encoding them only adds format overhead, so the result can match or even exceed the original. When that happens the tool keeps your original file untouched and tells you, so what you download is always the smaller of the two. If you want a genuinely smaller file from an already-optimised image, lowering the quality or converting the format is usually what does it.
Does compressing images help my website's SEO?: Yes, indirectly but meaningfully. Images are usually the heaviest part of a page, and lighter images make the page load faster, which improves your Core Web Vitals, in particular Largest Contentful Paint. Google uses page speed as a ranking signal and a faster page also keeps visitors from leaving, so compressing and serving images in a modern format is one of the highest-impact performance fixes available.

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