The quick rule
Use JPG for photographs, PNG when you need transparency or crisp edges (logos, screenshots, line art), and WebP when you want the smallest file and your audience uses modern browsers — which today is nearly everyone.
- JPG — photos and complex images without transparency.
- PNG — transparency, sharp text, flat graphics, screenshots.
- WebP — best overall compression for the web; supports transparency too.
When in doubt, convert for web
If your goal is a fast-loading website, WebP almost always wins. It typically produces files 25–35% smaller than JPG at the same visual quality, and unlike JPG it can preserve transparency like a PNG. The Convert for Web tool targets WebP by default.
Watch out for transparency
Converting a transparent PNG to JPG will fill the transparent areas with a solid color, because JPG has no alpha channel. If you need to keep transparency, convert to WebP instead, or keep the PNG.