Image Compressor
Shrink, convert and resize images in your browser. They are never uploaded — no sign-up, no watermark, no limit.
Table of contents
How to compress an image
- 1
Drop your images in
One or a hundred. They are read straight from disk into the page — nothing is uploaded, and you can disconnect from the internet first if you would like to prove it.
- 2
Pick a format
WebP is the default because it is usually far smaller than JPEG at the same visual quality. Choose JPEG for maximum compatibility, or PNG when you need every pixel kept exactly.
- 3
Set the quality, and resize if you want to
Around 80% is generally indistinguishable from the original. Most photos destined for a website are also far larger than they need to be, so capping the longest edge often saves more than quality alone.
- 4
Save them
Each image individually, or the whole batch as a zip. The originals on your disk are untouched.
The pixels you cannot see are the ones costing you
Most oversized images on the web are not badly compressed. They are simply far bigger than the space they are shown in. A photo straight off a modern phone is around 4000 pixels wide; the column it ends up in is often 700. That image is carrying more than thirty times the pixels anyone will ever look at, and no quality slider recovers that waste.
Resize first, then compress. Capping the longest edge near the size it will actually be displayed at routinely takes 80% off the file before quality is touched at all — and unlike lowering quality, it costs nothing visible, because the detail being discarded was never going to reach a screen.
Then let the format do the rest. WebP at quality 80 is usually a third of the original JPEG and visually identical at normal viewing size. The two together are the difference between a page that loads instantly and one that does not.
Why this one does not upload anything
Nearly every image compressor works the same way: you upload your photos, a server processes them, and you download the results. It works, and it means handing a stranger a copy of every picture you compress — including the ones you were compressing precisely because you were about to share them somewhere careful.
There is no technical need for any of that. Browsers have been able to decode, resize and re-encode images natively for years. This tool reads the file from your disk, draws it into a canvas at the size you asked for, and asks the browser to encode it. The photo never becomes a network request, so there is no upload to interrupt, no queue to wait in, and no retention policy to read.
It also means the honest limits are your own. Nothing is capped at ten files or five megabytes to push you toward an account, because there is no server cost for us to ration.
Frequently asked questions
No. The file is read from your disk into the page, decoded by your browser, redrawn at the size you asked for and re-encoded — all on your own machine. You can open the network panel and watch it stay silent, or load the page and disconnect from the internet before adding a single image. Nothing is sent, nothing is stored, and there is no queue on a server somewhere holding your photos.
WebP unless you have a reason not to: at the same visual quality it is typically 25–35% smaller than JPEG, and every browser in current use supports it. Choose JPEG if the file has to open in something old or in software that predates WebP. Choose PNG only when you need exact pixels — screenshots of text, images with sharp edges, or anything with transparency you cannot afford to approximate.
Because PNG is lossless, so re-encoding it cannot invent savings — and if the original was written by a tool with a better compressor than a browser has, the result can come out slightly larger. The fix is usually to convert rather than recompress: the same image as WebP will almost always be dramatically smaller. The tool tells you honestly when the output grew rather than quietly claiming a saving.
Start at 80. For photographs the difference from the original is very hard to see, while the file is often a third of the size. Below about 60 you start to see blocking in skies and smooth gradients. Above 90 the file grows quickly for very little visible gain. Images with text or sharp graphics show artefacts sooner, so keep those higher — or use PNG.
Very often, yes. A 4000-pixel photo displayed in a 800-pixel column is carrying twenty-five times more pixels than anyone will see, and no quality setting recovers that. Capping the longest edge at something near its real display size usually saves more than any amount of quality tuning, and it costs nothing visible.
None from us, because we never receive them. The real limit is your device: every image is decoded into memory, so a very large batch of very large photos will eventually run a phone out of room. On a laptop, hundreds of ordinary photos is fine. Nothing is queued, throttled or reserved for a paid tier.
Yes, as a side effect of how it works. The image is redrawn from its pixels, so camera settings, timestamps and GPS coordinates do not survive into the output. If you want to see what was in there first, or remove metadata without recompressing the image at all, use the EXIF viewer instead — it strips the data losslessly and leaves the pixels untouched.
It can, and that is worth understanding. Lossy formats lose a little each time they are re-encoded, so compressing an already-compressed JPEG twice is worse than doing it once well. This tool always works from the original file you dropped in, so changing the quality slider re-encodes from that original rather than stacking loss on loss.
They are not supported, and being straight about why: only Safari can decode HEIC, so a tool that offered it would work for some visitors and silently fail for the rest. Sharing or emailing a photo off an iPhone usually converts it to JPEG on the way out, which this handles fine.
No. No sign-up, no watermark, no daily limit, no "upgrade for full resolution". You get the full size of whatever you put in, every time. It is MIT licensed and the code is a few hundred lines you can read.
The Zeal Promise
Non-negotiable, on every tool we ship.
- No sign-up — ever
- No watermarks on any output
- No ads near the download button
- Works fully on mobile
- Privacy-first: processing stays in your browser
- Open source (MIT) — audit it, contribute, self-host
- Zero runtime dependencies in tool logic