How to use it
Drop your images onto the page, or press Select files. Everything happens in your browser: the file is read from your device, processed on your device, and never sent anywhere. There is no upload step, no queue, and no account.
Pick a preset under Algorithm. Balanced is the default and a reasonable starting point. Then move the Quality slider — higher keeps more detail and makes a bigger file. Press Compress, look at the before and after, and save the ones you want.
If you need a specific size rather than a specific quality — a form that caps uploads at 2 MB, an email attachment limit — switch Mode to Target file size and type the number. The tool searches the quality scale for the largest quality that still fits, then confirms that one step higher would overflow it. When nothing fits, it shrinks the image instead of squeezing it into mush.
Limits
Up to 20 files at once, 25 MB each. Inside those numbers, no account and no daily quota.
Save all packs the results into one ZIP, and that ZIP has a 200 MB ceiling. The ceiling is lower than 20 × 25 MB on purpose: assembling a bigger archive in a single tab can crash a mobile browser. If you hit it, save in two batches.
There is also a pixel limit. Images above roughly 80 megapixels are refused rather than allowed to exhaust memory.
Frequently asked questions
Does it upload my files?
No. The page downloads a WebAssembly build of the encoder and runs it locally. Your file is read from disk and processed inside the tab. Nothing is transmitted, and there is no server holding a copy.
Why is the result bigger than the original?
Almost always because the original was already compressed at a lower setting. Re-encoding at a higher setting asks the encoder to reproduce detail that is no longer there, and it spends bits describing the previous compression instead. When that happens this tool keeps your original file and tells you why, rather than handing you a worse file with a bigger size.
Why do compressed photos look slightly wrong in the colours?
Most compressors drop the colour sampling to 4:2:0 for every file, which throws away three quarters of the colour data before any quality setting is consulted. That is the usual cause. This one reads your file's original sampling and writes it back unchanged — the Keep original colour sampling checkbox controls that, and it is on by default.
What quality should I pick?
80 is the default and a fair starting point. Raise it to 85 or 90 when the image contains text, fine detail or saturated colour. Go below 70 only when file size matters more than the picture.
Can I compress a PNG?
Yes — switch to the PNG tab on the compression page. PNG is lossless, so you get two paths: lossless recompression, where every pixel stays bit-for-bit identical and files typically get 5 to 80 percent smaller, or a palette reduction when you need more than that, which is lossy.
What does Target file size actually do?
It searches the quality scale for the largest quality that still fits under the number you typed, and checks that one step higher would exceed it. If no quality reaches the limit, it shrinks the image instead — a small file is usually about pixel count, not about squeezing harder.
Why does Save all give me a ZIP instead of the files?
Because iOS blocks a series of downloads from one page, and one archive works everywhere. The archive has its own size ceiling, shown under Limits above.
What happens to EXIF and GPS data?
They are kept by default, so the output carries the same metadata as the input. If you want them gone, the Remove metadata page strips them without re-encoding the image: the pixels are untouched, only the hidden data is removed.
Can I convert WebP to JPEG?
Yes, on the Convert format page. Start at quality 90. Any transparency in the source is flattened onto white, because JPEG has no alpha channel — that is a real change to the picture, so check the preview.
Why can't I choose AVIF?
The option is hidden when your browser cannot encode AVIF. It is removed rather than shown and left to fail, so every format you can see is one the tool can actually produce.
Is there an account or a daily limit?
No account, no daily quota, no watermark, no sign-up. Images are not counted, tracked or rate-limited.
Does it work offline?
After the first load the encoder is cached, but there is no service worker, so a full reload without a connection will fail. Open the page once while online and it will keep working from cache for a while.
Where do the numbers on this site come from?
From measurements we ran and published in full. The chroma subsampling cost, what each encoder preset actually saves, whether the default preset was the right choice, and how much lossless PNG recompression removes are each written up with the method and the raw numbers. Start with what chroma subsampling costs, or what our own UI numbers got wrong.