Image Compressor
Compress and convert images to WebP, JPEG or PNG. Files never leave your browser.
Runs entirely in this tab — nothing is uploaded
or drop them here
Results appear here.
What this tool does
Drop in images, pick a format and quality, get smaller files back. Batch processing, with a before/after size for every file.
The images are decoded and re-encoded by your own browser. Nothing is uploaded — which also means there’s no queue, no file-size tier, and no retention policy to read.
Reading the output
Each result row shows the original size, the new size, and the change. A negative change means the file got bigger — see below for why that happens.
Processing happens in a Web Worker, so the page stays responsive and the Cancel button actually works mid-batch. Files already finished when you cancel are kept.
Choosing a format
WebP is the default and the right answer most of the time — typically 25–35% smaller than JPEG at visually equivalent quality, with support in every current browser.
JPEG is the safe choice for compatibility with old software, email clients, and print workflows. No transparency.
PNG is lossless, so the Quality slider does nothing. Use it for screenshots, diagrams, line art, and anything with sharp edges or flat colour — and expect files to be much larger than WebP for photographs.
Why a file sometimes gets larger
This surprises people, so it’s worth stating plainly:
- Re-encoding an already-compressed JPEG at high quality. The source has already thrown away detail; encoding it again at quality 0.95 spends bytes preserving compression artefacts. Lower the quality, or leave the file alone.
- Converting a photo to PNG. PNG is lossless and terrible at photographs. A 200 KB JPEG can become a 2 MB PNG.
- Very small images. Format headers are a fixed cost. Below a few kilobytes, that overhead can exceed the savings.
Resizing
Max width scales images down proportionally; 0 keeps the original dimensions. Images already
narrower than the limit are left alone — it never upscales.
Resizing is usually a bigger win than quality tuning. Halving the width of a photo removes about three-quarters of the pixels, which beats anything the encoder can do.
Limits
Total input is capped at 50 MB per batch, which is a deliberate guard rather than a technical ceiling. Browsers on phones have roughly 1–2 GB of memory per tab, and exceeding it crashes the page outright — the crash cannot be caught and reported, so the cap keeps you on the safe side. For very large batches, process in groups.
HEIC files from iPhones cannot be decoded by browsers. There is no way around this without shipping a multi-megabyte decoder. Export as JPEG from Photos first.
FAQ
Does this strip EXIF data? Yes, as a side effect. Re-encoding through a canvas drops all metadata, including GPS coordinates. That’s good for privacy, but it also means camera settings and orientation tags are gone. If your image relies on an EXIF orientation flag, verify the result.
Can I keep transparency? Use WebP or PNG. Converting a transparent image to JPEG fills the transparent areas with black.
What quality should I use? Start at 0.8. Below about 0.6, artefacts become visible on photographs; above 0.9 you’re mostly adding bytes.
Is my image uploaded? No. Open DevTools, switch to the Network tab, and compress something. Zero requests.