Re Preview Support for Webp images?
(This is in response to an earlier question titled "Preview Support for Webp images?" which is now locked – in case anybody else is looking for an answer.)
Downloaded an image from a Web page via Vivaldi; it appeared in Finder as a .webp file. According to ⌘I Get Info, it opens in Preview (default). Double-click the file, Preview opens, but shows nothing. Preview then shows the file under Open Recent…, but still won't open it. Same result in both Sierra and Catalina.
Downloaded the image again, in both Vivaldi and Brave (both based on Chromium), looked more closely, saw only two Format options: Google WebP and "All Files" (which produces a file without an extension that MacOS will open in TextEdit as plain text).
However, when I opened the Web page in Safari and downloaded the image, either by Save Image As… or Save Image to "Downloads", it was automatically converted and appeared in Finder as a .png (the only choice in the Save As dialog), which opened fine in Preview.
Also, when I copied the image from the Web page to the clipboard, then opened Preview and selected New from Clipboard ⌘N, it created a new Untitled document, which could then be saved as a .png.
Weird, but at least there seems to be a solution (or two). According to Wikipedia:
In early beta versions of macOS Sierra and iOS 10, Apple added WebP support, but [it] was later removed…. WebP is unsupported in macOS and iOS Safari browser version 13 or lower. However, support is being added in Safari version 14.
However, the .webp image appears just fine in Safari 12.1.2 in MacOS 10.12 Sierra, and saves as a .png (as described above), though it can't be opened in Preview. The image also appears on the Web page in Safari in iOS 12.4.8 (iPad Air), and saves to Photos (don't know in what format). So there is partial support in both OSes. Weird, but workable.
MacBook Pro 15″, macOS 10.12