I don’t know what a .webp file is but I don’t like it. They’re like a filthy prank version of the image/gif you’re looking for. They make you jump through all these hoops to find the original versions of the files that you can actually do anything with.
I often will use the Windows Snipping Tool to screenshot, then copy/paste the screenshot. This also works around sites trying to block you from right-clicking images. Granted you’re limited to screen resolution then but web images are almost always so tiny anyways that makes little difference most of the time