Image Compressor

No. The file never leaves your browser: decoding, scaling, and re-encoding all happen with the Canvas API in your tab. Closing the tab discards everything. That is why this tool works offline once the page is loaded, and why it suits confidential screenshots or client artwork.

JPEG is always lossy: discarding detail is how file size drops. Higher quality presets keep more detail but shrink less. PNG re-encode from this tool is lossless for the pixels on the canvas, but if you downscale resolution you permanently reduce fine detail—keep originals when you might need them later.

Photos and gradients usually compress much smaller as JPEG. UI shots, logos, or anything needing sharp edges or transparency should stay PNG (or WebP elsewhere). If you force a photo to PNG, expect much larger files than a sensible JPEG at 80–90% quality.

If your image is wider than the limit you set, we proportionally shrink both dimensions so the long side matches that pixel width. That alone can slash megabytes on phone photos meant for the web. Set 0 to keep original pixel dimensions and only change format/quality.

Very noisy or high-resolution sources have more information to encode. Try a lower JPEG quality, enable max width, or switch to PNG only if transparency needs it—otherwise JPEG often wins. Animated formats and some RAW-like files are not special-cased; you get one raster frame after decode.

Practical limit is your device RAM: gigapixel jokes aside, tens of megapixels are usually fine. Very old browsers may lack modern canvas MIME support; use an up-to-date Chrome, Edge, Firefox, or Safari. HEIC/HEIF may fail unless the OS exposes a decodable type the browser understands.