Compress images
Most compressors give you a quality slider and let you guess. This one takes a number — say 100kb — and searches for the highest quality that still fits under it. Everything happens in this tab.
Compressing to a specific size
Upload limits are stated in bytes, not in quality percentages. A job application wants a photo under 500 KB; a forum caps avatars at 100 KB; an email gateway rejects anything over 2 MB. Pick A file size, type the limit, and the tool encodes the image several times over, narrowing in on the best quality that still comes in under your number. It usually settles in about seven attempts, which is fast enough that you will barely notice.
Which format should you choose?
WebP is the sensible default in 2026 — every current browser reads it, and it is typically 25–35% smaller than JPEG at matching quality. AVIF goes smaller still, often dramatically so on photographs, but takes longer to encode and is a poor choice if the file has to open in older desktop software. JPEG is the one that opens absolutely everywhere. PNG is lossless, so use it for screenshots, diagrams, logos and anything with sharp edges or text — and never for photographs, where it will be enormous.
Quality 100 and lossless
Pushing the slider to 100 does different things depending on the format. WebP and AVIF switch to a genuinely lossless mode — every pixel survives, and the file is often still smaller than the PNG you started with. JPEG has no lossless mode at all, so 100 is simply its highest lossy setting: very close to the original, and a large file. PNG ignores the slider entirely because it is always lossless.
Checking the result before you commit
Every finished image gets a before-and-after view with a divider you can drag across it. Compression artefacts hide in skies, skin tones and flat gradients, and they are almost impossible to judge from a file size alone. Drag the divider over those areas at full size — if you cannot see the seam, the setting is fine. Click any row in the list to compare that image.
Why not just use the quality slider?
You can, and for a single image it is often quicker. Quality numbers are not comparable across formats though — WebP at 80 and JPEG at 80 are different encoders making different trade-offs. If you have a hard limit to hit, the size search removes the guesswork.
Where the savings come from
This page uses purpose-built compressors compiled to WebAssembly rather than the browser's own quick-and-dirty encoder. They are slower by a few hundred milliseconds and noticeably better at keeping detail for a given file size, which is the trade worth making when you are compressing on purpose. The relevant compressor downloads the first time you pick a format and is cached after that.
Frequently asked questions
Are my images uploaded?
No. Compression runs inside this browser tab. There is no upload endpoint and nothing is stored. Load the page, go offline, and it still works.
Can I compress a batch?
Yes. Drop as many as you like; they run a few at a time so a phone does not run out of memory. Each gets its own download button as it finishes.
Why is my PNG barely smaller?
PNG is lossless — it can only pack the same pixels more tightly, not throw any away. Photographs have too much detail for that to help much. Switch to WebP or AVIF and the same picture will typically drop by 70% or more.
Can I resize at the same time?
Not on this page yet. Halving an image's dimensions cuts the file to roughly a quarter, so it is often the better lever — the editor can resize and export today.
My target size is impossible to hit.
If even the lowest quality overshoots your limit, you get the smallest result the encoder managed, rather than an error. The image is probably too large in pixel dimensions — reduce those first.