Why sites serve WebP
Smaller images mean faster pages, and page speed affects both user experience and search ranking. WebP usually undercuts JPEG at the same visual quality and undercuts PNG for graphics with transparency, which is why performance-focused sites convert their assets.
The compatibility catch
Every modern browser displays WebP, but desktop software, printers, government and enterprise upload portals, and older devices often don't. When a form rejects your image or a client can't open it, converting the WebP to JPG or PNG solves it in seconds. One quirk worth knowing: Safari can display WebP but cannot create it, so browser-based converters fall back to other formats there.