Convert PNG images to WebP in the browser via the Canvas API. PNG is often lossless and bulky for photos or soft gradients; lossy WebP with an adjustable quality slider usually yields a much smaller file for web delivery.
How it works
The tool loads a local .png, draws pixels to a canvas, and encodes with image/webp at your quality setting. Alpha transparency is typically composited onto an opaque background when the encoder path flattens the bitmap—expect solid backing rather than a preserved alpha channel unless the browser keeps it for that MIME path.
When to use it
- Shrink UI screenshots or marketing PNGs for faster loads
- Preview WebP quality before scripting a bulk converter
- Replace oversized PNG exports from design tools
Limitations
Animated PNG (APNG) is unsupported. Color profiles and bit depth may change. Lossless PNG sharpness on text/UI can degrade under aggressive lossy quality. Very large canvases may fail or stall.
Example
A 1600×900 PNG screenshot around 1.8 MB at quality 0.75 often compresses to a WebP under 400 KB; raising quality to 0.95 keeps crisper edges at a larger size (for example ~700 KB).