Compress an Image
Pick an image, choose a quality — it's re-encoded smaller in your browser, nothing is uploaded.
Compress an image in your browser
Pick an image, set a quality, and get a smaller copy that keeps the same format (JPG stays JPG, PNG stays PNG, WebP stays WebP). The re-encoding runs entirely in your browser with ffmpeg compiled to WebAssembly — your image is never uploaded to a server.
How quality works
- JPEG / WebP are lossy: a lower quality throws away more detail for a smaller file. Quality 80 (the default) is a good size/quality balance; drop to 50–60 for a noticeably smaller file.
- PNG is lossless, so quality never changes how the image looks — it only tells the encoder how hard to compress. PNG savings are limited; if you need a much smaller file, convert it to WebP or JPEG first.
Tips
- Leave the quality field blank to use the default (80).
- Works offline once the page has loaded.
- To shrink an image to specific pixel dimensions instead, use the resize tool.
FAQ
Which image formats can I compress?
JPG/JPEG, PNG, and WebP — the format is inferred from the file extension and the output keeps it. Other formats (GIF, BMP, TIFF, …) are rejected; convert them to one of the three supported formats first.
I lowered the quality but my PNG looks identical — is it working?
Yes. PNG is a lossless format, so quality can't change the pixels. Instead it tunes the encoder's effort: a lower quality value asks for harder compression (quality 1 maps to the maximum compression level 9), which trades CPU time for a somewhat smaller file.
Can the "compressed" file come out bigger than the original?
It can, if the source was already efficiently encoded — re-encoding a well-optimized JPEG at a high quality setting may add bytes rather than save them. If that happens, try a lower quality, or convert the image to WebP, which usually beats JPEG and PNG at the same visual quality.
What does the default quality 80 actually do?
For JPEG, the 1–100 scale is mapped onto ffmpeg's -q:v 31 (worst) to 2
(best), so 80 lands around 8 — a solid size/quality balance. For WebP the
value is passed to the encoder directly, and for PNG it selects the
compression effort.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool image-compress 'url=https://example.com/input' 'quality=80'New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/image-compress/?url=https://example.com/input&quality=80Machine-readable descriptor: tool.json — title + parameters JSON Schema for agents.