Changing a filename from .png to .jpg does not convert an image. Toolkatsu decodes the source and writes a new file in the selected format. The Convert tab keeps the original pixel dimensions.
| Format | Useful for | Watch for |
|---|---|---|
| JPG | Photographs and forms that require JPEG | No alpha transparency; lossy encoding |
| PNG | Screenshots, sharp text and transparent graphics | Photographs can become much larger |
| WebP | Web images with optional transparency | Some upload forms do not accept it |
Transparency example
A transparent logo converted to JPG receives a white background in Toolkatsu. Converting that JPG back to PNG does not restore the removed transparency. To preserve the alpha channel, convert the original PNG directly to WebP or keep PNG.
Quality and size
PNG output does not restore detail that a JPG has already lost. Repeated lossy conversions can introduce additional artifacts, so start from the best original. Format conversion is not a promise of smaller files: inspect the result size, then use Compress if needed.
Supported inputs
Only still JPG, PNG and WebP inputs are supported. GIF, HEIC, SVG, animated PNG and animated WebP are not supported in this version. Output encoding relies on your browser; if an encoder is unavailable, the tool shows an error rather than changing the extension alone.