Image Compressor
Shrink JPG, PNG and WebP images without uploading them anywhere. Drop in a batch, set the quality, optionally cap the dimensions, and see the before and after size for every file plus the total saved. Re-encoding happens on a canvas in your own browser, so the images never leave your device. Free, no signup.
Add images to compress
Drag and drop, or click to choose. JPG, PNG, WebP or GIF. Batch supported.
Compressed images appear here. Nothing is uploaded — everything happens in your browser.
How to Use This Tool
- Add your images — drag and drop them onto the box or click to browse. You can add up to 30 at once.
- Set the quality — around 80 percent is the usual sweet spot for photos. Lower it further if the file still needs to shrink.
- Pick a format and size cap — WebP usually wins on size, JPEG is the safest for photos, PNG stays lossless. Cap the longest edge to cut large uploads down first.
- Download — grab files one at a time or use Download all, and check the savings figure before you ship them.
About Image Compression
Images are almost always the heaviest thing on a web page, and compression is the cheapest performance win available. Cutting a 2 MB hero photo to 200 KB does not just make the page load faster; it directly improves Largest Contentful Paint, which is one of the Core Web Vitals that Google uses as a ranking signal. It also reduces bandwidth costs and makes the site usable on a slow mobile connection, which is where a large share of real traffic actually comes from. The work is mechanical, which is why it should be automated rather than done by eye.
The first thing to understand is lossy versus lossless. Lossy compression, used by JPEG and by WebP in its default mode, permanently discards information the eye is unlikely to miss, and it achieves dramatic size reductions as a result. Lossless compression, used by PNG and by WebP in lossless mode, reorganises the data so the original can be reconstructed exactly, which is safer but far less effective on photographs. The important consequence of lossy compression is that it compounds: every save throws away more detail, so you should always compress from the original rather than repeatedly re-saving an already compressed file.
Format choice matters more than the quality slider. JPEG suits photographs and any image with smooth gradients, but it has no transparency and produces visible ringing around sharp edges and text. PNG is the right choice for logos, screenshots, line art and anything that needs an alpha channel, but it is a poor fit for photos and will often produce a file several times larger than the JPEG equivalent. WebP is generally the best of both, typically 25 to 35 percent smaller than an equivalent JPEG while also supporting transparency and animation, and it is supported by every current browser.
Quality settings are less intuitive than they look. The number is not a percentage of anything meaningful, it is a knob on the encoder, and the relationship between it and file size is steeply non-linear. Moving from 100 to 90 typically removes half the file size for almost no visible change, while moving from 60 to 50 saves comparatively little and starts producing obvious blocking. For photographs, somewhere between 75 and 85 is the usual sweet spot. Images with large flat areas or text tolerate compression much worse, which is why a screenshot at quality 80 can look noticeably worse than a photo at the same setting.
Two behaviours here are worth flagging. Converting a transparent PNG to JPEG has to flatten the transparency onto something, because JPEG has no alpha channel; without that step the transparent areas turn black. This tool composites onto white by default. And compression can occasionally make a file bigger, which sounds like a bug but is not: if the source was already well optimised, or you are re-encoding a photo as PNG, the output legitimately grows. The tool tells you when that happens rather than silently handing you a worse file. For a site-wide fix, though, the real answer is an automated pipeline with responsive srcset images and a CDN, not a manual pass.
Pair this with our Image Resizer to cut dimensions before compressing, the Image to WebP Converter for format migration, and the Favicon Generator for icon sets.
Frequently Asked Questions
What is the difference between lossy and lossless compression?
Lossy compression permanently discards image data that the human eye is unlikely to notice, which is how JPEG and default WebP achieve very large size reductions. Lossless compression reorganises the data so the original can be rebuilt exactly, which is what PNG and WebP lossless mode do. The practical difference is that lossy compression compounds: each save discards more detail, so repeatedly re-saving a JPEG will visibly degrade it over time. Always compress from your original file rather than from an already compressed copy, and keep the original somewhere safe.
What quality setting should I use?
For photographs, between 75 and 85 is the usual sweet spot, and 80 is a sensible default. The relationship between quality and file size is steeply non-linear: dropping from 100 to 90 often halves the file for no visible change, while dropping from 60 to 50 saves little and introduces obvious blocking. Images with large flat areas, sharp edges or text tolerate compression much worse than photos, so a screenshot at quality 80 can look considerably worse than a photograph at the same number. Always look at the result rather than trusting the setting.
When should I use JPG, PNG or WebP?
Use JPEG for photographs and anything with smooth gradients; it is universally supported and very efficient on that kind of content, but it has no transparency and blurs sharp edges. Use PNG for logos, icons, screenshots, line art and anything needing an alpha channel, accepting that it will be large for photographic content. Use WebP as the default for web delivery: it is typically 25 to 35 percent smaller than the equivalent JPEG, supports transparency and animation, and works in every current browser. The main reason to avoid WebP is a workflow that has to hand files to older desktop software.
Does image compression affect SEO?
It helps, and quite directly. Images are usually the largest assets on a page, so compressing them improves Largest Contentful Paint, one of the Core Web Vitals that Google uses as a ranking signal. Faster pages also reduce bounce rate and improve conversion, both of which matter commercially even where they are not ranking factors. What does not help is over-compressing to the point of visible artefacts, since image quality affects perceived credibility. Compression is one part of the job: also serve responsive sizes with srcset, set explicit width and height to avoid layout shift, and lazy-load anything below the fold.
Is WebP supported everywhere?
Yes, for practical purposes. WebP is supported in Chrome, Edge, Firefox, Safari and all current mobile browsers, covering roughly 97 percent of users. Safari was the last holdout and added support in 2020. The remaining gap is old software rather than browsers: some desktop image editors, email clients and content management systems still handle WebP poorly. If you need a fallback, the picture element with multiple source entries lets the browser choose WebP where available and JPEG otherwise. This tool checks your browser directly and disables the WebP option if it cannot encode it.
Does compression remove EXIF data?
Yes. Because the image is decoded and re-encoded through a canvas, all metadata is dropped, including EXIF, camera settings, timestamps, copyright fields and any embedded GPS coordinates. For web publishing this is usually a benefit: it removes a privacy risk, since photos taken on a phone frequently carry the exact location where they were shot, and it shaves a little more off the file size. It is a genuine loss if you need to preserve copyright metadata or camera information, so keep your originals and treat the compressed files as web derivatives.
What happens to transparency when I convert PNG to JPG?
JPEG has no alpha channel at all, so the transparency has to be flattened onto something. If it is not handled, transparent areas typically render as black, which is the single most common surprise when converting logos. This tool composites onto a white background by default, and you can switch that off if you want the raw behaviour. If transparency matters to your image, the answer is not to convert to JPEG at all: keep it as PNG, or use WebP, which supports both transparency and lossy compression and will usually be smaller than the PNG.
Are my images uploaded to a server?
No. Every file is read locally with the browser FileReader API, decoded into an image, redrawn on a canvas and re-encoded, all on your own machine. Nothing is transmitted, nothing is logged, and no copy is retained after you close the tab. That makes the tool safe for client photography, unreleased product shots, internal screenshots and anything else under NDA. The practical trade-off is that processing is limited by your device: very large batches or very high-resolution files will be slower than a server-side service, and extremely large images are refused rather than risking a browser crash.