My opinion is that WEBP sucks. It's SOMETIMES a bit smaller in filesize than JPG or PNG but the usability and compatibility problems are too great and disk is ludicrously cheap nowadays, so universal compatibility with long-time standard formats wins easily.
These two command lines will, in just seconds, convert all the .webp files in a directory to either JPG or PNG (your choice, PNG for line art or screenshots and the like or for continuous-tone photos where mathematically-perfect preservation of all pixel values is required (rare), and JPG for continuous-tone photos where very good indeed but not perfect quality is acceptable (which is almost always)).
These work at least as far back as Easy Buster and they work fine on Kirkstone too, and you don't need to install any more software, it's all already baked into Easy:
for i in *.webp ; do ffmpeg -i "$i" "${i%.*}.png" ; done
for i in *.webp ; do ffmpeg -i "$i" "${i%.*}.jpg" ; done
When I get one or more WEBP files, I make an empty directory (or use an existing one), put the WEBP file(s) in there, then open a shell and "cd" to that directory, then I use one of the command lines above. Watch for red errors in the spam (almost never are any), then check that your new PNG or JPG files look good and are viewable, then delete the crappy WEBP versions. That's it, you're done!
I never store WEBP files; when I download one or more, they get immediately converted to PNG or JPG and those get stored, with the WEBP files deleted.
Note that while converting to PNG preserves all the pixel data in the WEBP source file perfectly, JPG does not (but it's much smaller in filesize). In my long experience with the commandlines above, ffmpeg makes quite good choices for what quality level to use for the JPG conversions and the quality is well beyond that needed for casual viewing, but if you're a perfectionist or want to archive in the highest quality, either use PNG or use a more complicated set of tools to hand-tune the JPG output to your needs. It shouldn't be necessary often though.
Incidentially, this commandline will batch-convert all PNGs in a directory to JPG, for those websites that annoyingly give you large-dimensions images in PNG format and they're just for casual viewing, and you'd prefer to convert and store them as JPG which typically reduce their filesize to about 1/20th (5%) of the PNG original while retaining very nearly all of the quality (more than enough for simple viewing). It's a GREAT way to fit 20 times as many images on a given storage device. Don't do this for charts, graphs, screenshots, etc., only do it for what JPG is designed for: continuous-tone, high-color, photo-like images:
for i in *.png ; do ffmpeg -i "$i" "${i%.*}.jpg" ; done
This is incredibly useful after downloading a whole bunch of huge PNG files where you don't need perfect mathematical accuracy. 20-to-1 size reduction on ALL of them in SECONDS!
Hope that helps!
