I haven’t tried it in the Photos app recently, and don’t have a Windows system handy right now to try it out, but I know it works for sure in Paint, which uses GDI+ for image encoding/decoding (and thus supports all formats that Windows itself supports).
Of course, apps that use their own encoding/decoding code might have fewer features and support fewer formats than the native Windows code.
Edit: Apparently it works fine in the Photos app if you just change the extension? Which means Microsoft is doing something weird. The code to decode WebP must be there.
The built-in APIs for handling images (GDI+) added WebP support in 1809.
The end user doesn’t work with Windows API. The end user works with web sites and apps, which are rarely native these days. And there you’re often limited to png/jpg for uploads.
The built-in APIs for handling images (GDI+) added WebP support in 1809. This is mentioned in the the documentation for the drawing library in C#/.NET, which is a wrapper around GDI+: https://learn.microsoft.com/en-us/dotnet/api/system.drawing.imaging.imageformat.webp?view=net-8.0
I haven’t tried it in the Photos app recently, and don’t have a Windows system handy right now to try it out, but I know it works for sure in Paint, which uses GDI+ for image encoding/decoding (and thus supports all formats that Windows itself supports).
Of course, apps that use their own encoding/decoding code might have fewer features and support fewer formats than the native Windows code.
Edit: Apparently it works fine in the Photos app if you just change the extension? Which means Microsoft is doing something weird. The code to decode WebP must be there.
The end user doesn’t work with Windows API. The end user works with web sites and apps, which are rarely native these days. And there you’re often limited to png/jpg for uploads.
Again, barely lol