A private image compressor — no uploads, by design
Most "free online image compressors" work by uploading your photos to their servers, processing them there, and letting you download the result. That means your images — vacation photos, ID scans, screenshots with personal information — travel to and sit on someone else's computer. This tool takes the opposite approach: it uses your browser's built-in Canvas API to re-encode images on your own device. Nothing is transmitted, nothing is stored, and the tool keeps working even if you go offline after the page loads.
Compression works by re-encoding the image at a chosen quality level. JPEG and WebP are lossy formats: they discard detail your eye barely registers, which is why dropping quality from 100% to 80% often cuts file size by 60–90% with no visible change at normal viewing sizes. PNG is lossless — the quality slider doesn't apply — so for PNGs the real savings come from resizing or converting to WebP. Resizing matters more than people expect: a 12-megapixel phone photo is 4000 px wide, but no web page or email needs more than ~1920 px, and halving each dimension cuts the pixel count (and roughly the file size) to a quarter.
JPEG vs PNG vs WebP — which to use
| Format | Type | Transparency | Best for | Typical size* |
|---|---|---|---|---|
| JPEG | Lossy | No | Photos; maximum compatibility (email, old software) | 100% |
| WebP | Lossy or lossless | Yes | Everything on the modern web — smallest files | ~65–75% of JPEG |
| PNG | Lossless | Yes | Screenshots with text, logos, sharp-edged graphics | 3–10× JPEG for photos |
*At comparable visual quality for photographic content. For graphics with few colors, PNG and lossless WebP can be smaller than JPEG. Need an image as code instead? See the image to Base64 converter, or check dimensions for a layout with the aspect ratio calculator.
Frequently asked questions
- Are my images uploaded to a server?
- No. Everything happens locally in your browser using the HTML5 Canvas API. Your images never leave your device — there is no upload, no server-side processing and no storage. You can even load the page, disconnect from the internet and keep compressing.
- How does image compression work here?
- The tool re-encodes your image with the quality level you choose. JPEG and WebP are lossy formats: lowering quality discards visual detail your eye barely notices and shrinks the file dramatically. A quality of 75–85% typically cuts file size by 60–90% with no visible difference at normal viewing sizes. PNG is lossless, so for PNGs the biggest savings come from resizing or converting to WebP.
- Which format should I choose — JPEG, PNG or WebP?
- Use JPEG for photos when you need maximum compatibility. Use WebP for the web — it is 25–35% smaller than JPEG at the same visual quality and supports transparency. Keep PNG only for images that must stay pixel-perfect, such as screenshots with text, logos or graphics with sharp edges.
- Does compressing remove EXIF data like GPS location?
- Yes. Re-encoding through the canvas drops all metadata — EXIF camera settings, GPS coordinates, timestamps and embedded thumbnails. That is a privacy bonus: photos you share after compressing here no longer reveal where they were taken.
- What is the best size for web images?
- For full-width content images, 1280–1920 px wide at JPEG/WebP quality 75–85% is the sweet spot — usually 100–400 KB. Thumbnails rarely need more than 400 px. As a rule of thumb, no image on a normal web page needs to be wider than 1920 px or heavier than 500 KB.
- Why did my PNG barely shrink (or get bigger)?
- PNG is lossless, so the quality slider does not apply — the encoder can only repack the same pixels, and a browser's PNG encoder is often less efficient than the one that made the original. To make a PNG meaningfully smaller, resize it down or convert it to WebP (keeps transparency) or to JPEG if it is a photo without transparency.