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ImgCompress Image Compressor

PNG quantization · JPEG re-encode · WebP · all local

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Drop images here

or click to browse · multiple files supported · Ctrl+V paste · release anywhere on the page

PNG / JPEG / WebP / GIF (first frame) / BMP / AVIF supported, up to 50 MB each; drop a folder and images inside are picked up automatically. Images are compressed in your browser and never uploaded.

Compression settings

Output format
80
80

No images yet - drop a few above to try

What this tool is

ImgCompress is an image compressor that runs entirely in your browser, built around the same idea as TinyPNG: true-color PNG is reduced to a palette of at most 256 colors (Wu quantization + Floyd-Steinberg dithering), which typically saves 50%-80% on screenshots, illustrations and UI assets with no visible difference. JPEG is re-encoded with the same mozjpeg encoder Squoosh uses (trellis quantization + progressive), usually beating camera-originals and "Save As" exports at equal quality. WebP is there for when you want to go even smaller.

Everything happens on your device: decoding, quantization and encoding ship with the page (the encoder engine is fetched once, on first use), there is no upload endpoint and no server-side storage to worry about. Batch input, per-image comparison and one-click ZIP packing are built in, and every parameter is adjustable - defaults are close to TinyPNG's.

Features

How to use it

  1. Drag images into the dashed area (or click to browse, or paste with Ctrl+V) - the queue starts compressing automatically.
  2. Adjust output format and parameters in Settings; the queue re-compresses everything with the new values.
  3. Use Compare on any image to inspect the result; download single files or grab everything as a ZIP.
  4. Unhappy with quality? Raise the color cap or quality. Unhappy with size? Lower them - it is free to experiment since nothing is uploaded.

FAQ

Are my images uploaded?
No. The page is fully static; decoding, quantization and encoding run in your browser's WebAssembly. Watch the network panel - no image data ever leaves, the only request is the one-time download of the encoder engine itself.
Why is PNG compression "lossy"?
Same as TinyPNG: true-color images are reduced to a palette of at most 256 colors (the same family of algorithms as pngquant/libimagequant) - the savings come from fewer colors, not from lossless compression. Photos, screenshots and illustrations survive almost untouched; images with very subtle gradients may show mild banding - raise the color cap or switch to WebP.
When should I keep PNG, and when switch to WebP?
Screenshots, icons, line art and flat-color illustrations: PNG quantization works best and keeps transparency. Photos and gradient-heavy images: JPEG or WebP wins. Unsure? Compress both ways and compare - it costs nothing.
What happens to animated GIFs?
Only the first frame is taken and output as a static image - animated GIFs are effectively flattened; use a dedicated tool for those. BMP, AVIF and anything the browser can decode works too, output follows the target format you picked.
How does it differ from TinyPNG?
The official web tool caps at 20 files / 5 MB and charges for API use; this one has no file-count limit, accepts up to 50 MB per image, exposes every parameter, and runs fully locally. Compression ratios are on the same level (same family of algorithms), but byte-for-byte output will differ - every implementation quantizes and encodes JPEG slightly differently.

More tools on this site

Runs entirely in your browser · nothing uploaded · free · 中文 / 繁體 / English