Smaller photos, same look.

No. The encoder runs in your browser tab using the canvas API. Your photo never touches our servers — we don't run an image pipeline at all. Open DevTools → Network and watch: nothing leaves your device.

It depends on where your photo came from. On an original — a camera raw export, a screenshot, a rendered graphic — WebP came out about 20% smaller than JPG at matched quality in our tests (19.1 KB at 43.2 dB against JPG's 23.8 KB at 42.3 dB). On a photo that is already a JPEG, WebP lost: at the same file size, the JPG re-encode scored higher, because JPEG can reproduce the artifacts already in the file cheaply. Since most photos people bring here are already JPEGs, try both and read the byte count — the tool shows you the real number.

Because your original was already compressed harder than the setting you picked. A photo saved at quality 95 grew 52% in our tests, and the same photo saved as PNG grew more than nine times. That is not a bug in the encoder — it is what re-encoding an already-small file costs. The readout says “bigger” when that happens and offers your original back. Drop the quality, cap the pixel size, or keep what you have.

If your browser offers it, yes — AVIF was the clear winner in testing, about 4.7 dB better than JPG at the same file size, or roughly half the bytes for the same picture. The catch is support: only browsers that can actually encode AVIF show the button, so you will see it in Safari and not in Chrome, and some older apps still cannot open the files.

Only when you need lossless — diagrams, screenshots with text, anything you'll edit again later. PNG is much larger than JPG/WebP for photos and the quality slider doesn't apply.

75 for JPG and 70 for WebP are the sweet spots for the web — visually indistinguishable on a phone or laptop. Push past 90 only for print or large displays, and expect the file to grow if the original was already compressed. Below 60, banding and blocking start to show. If you have a hard limit to hit instead of a look to match, use the size target and let the tool search for the quality.

A modern phone shoots 4000–8000px wide. Almost no screen is bigger than 2400px. Resizing to 1920px before compressing cuts the file in half before quality even comes into play. Resize first, compress second.

Single-photo for now — the tool is built for quick, one-off compression. For batches of 50+ photos, a desktop app or a build script (sharp, ImageMagick) is the right tool.