Files stay on your device. Enter send · Esc close drawers
Smaller files for the web
Image formats trade off compression, transparency, animation, and browser support. Convert PNG → WebP converts your input to WEBP, which is the right choice when the destination supports modern formats and you want JPEG-quality at 25-35% smaller file size. WebP is supported by every browser shipped after 2020 and produces files 25-35% smaller than PNG with comparable quality. Use it where bandwidth matters and the recipient runs a modern browser. The preset outputs WebP at 80% quality entirely in your browser — the file is never uploaded to a conversion server, which matters when the source contains personal information like ID scans, screenshots of private documents, or proprietary design files.
| Output format | WEBP |
|---|---|
| Processing | 100% in your browser — no upload |
| Cost | Free, unlimited |
This preset is a deterministic recipe — every step has fixed parameters so the result is byte-identical across runs of the same input.
The format conversion runs through canvas APIs and a WebAssembly image-encoder. Decode and re-encode happen in your browser; the source file is never uploaded.
For input formats not natively decoded by the browser (HEIC, AVIF on older browsers, TIFF), Mochi falls back to a WebAssembly decoder shipped alongside the page.
WebP delivers ~25-35% smaller files than JPEG at equivalent perceived quality, and supports transparency. Modern browsers (2020+) all render it; older email clients may not.
Converting PNG → WEBP is lossy. The output is smaller because the encoder discards information the eye is unlikely to notice. At quality 92% (this preset's setting), the visible quality loss is minimal for photographic content but visible on hard edges (text, line art).
WebP usually runs 25-35% smaller than PNG with no perceptible quality difference. The actual ratio depends on image content — photographs follow the average closely, while screenshots and line art compress differently.
No. This preset runs entirely in your browser using WebAssembly + canvas APIs — no server round-trip. You can verify this in your browser's network panel: only static asset requests, no image upload. The file never leaves your device.