Changing the extension will also change the file. How is that possible ?
I had expected they will become webp files with the incorrect extension.
It's just a simple little trick that works most of the time (for pictures anyway). It's also a fairly popular "conversion" method, as you can just batch rename multiple files at once, and, if it turns out that the pic(s) get(s) darkened as a result from this, then you can still open the webp file(s) in MS Paint and save it/them as .jpg to work around that problem. I don't download webp files that often anyway, but if you do, then I can understand that you probably need a better solution.
That said, there does exist an official (from Google)
conversion tool,
dwebp, that lets you convert webp picture files to the png file format, but then you'd still need to convert from png to jpg next so, not exactly a handy solution either. A better solution IMO is this:
WebP is a new compressed image format developed by Google. If you want to convert WebP to any other format, you seem to be mostly out of luck if you are using C#. There is, however, some tools out …
briancaos.wordpress.com
Only one small problem, the two dll files (
libwebp_x64.dll and
libwebp_x86.dll) still need to be compiled for that to work, as the libwebp-1.2.4.tar.gz archive that you can download from Google only contains the source code written in C++ so, to be able to run
nmake like described
here, you need to have Visual Studio.
Visual Studio 2022 Community Edition – Download Latest Free Version
(Nowadays
VS Code also lets you use makefiles via an official plugin for it from Microsoft, but I haven't tried that myself.)
On a side note, the day before yesterday I had received four jpeg photos via email and I tried to open them with the Photo app after saving them to a new folder onto my desktop. One of these files refused to show up on the filmstrip control at the bottom. Doubleclicking on the file in File Explorer opened the file just fine, BUT... strangely, this time around, another one of the four files was missing from the filmstrip. The old Windows Photo Viewer program had no such problems, it displayed a fullscreen slideshow of all four of the files without the slightest hitch. This new Photo app is still an absolute POS. Who knows maybe one day they might finally get it right.