The screenshot in the first post doesn’t look like that - the icons are there, just what appears to be picture files on the left side don’t have a proper icon.
… although I do not know what the pinta window is supposed to look like, which icons might be missing …
I guess that was intended as an answer to:
pinta is only available from the AUR
which means: you did not update/rebuild it,
because pacman cannot do that.
@psionman Maybe just use the flatpak or snap version that is maintained directly by the developer. Since this is tested by the developers, not maintained and tested by some random guy on the AUR.
I just did the same - but it was a new install to test it, not a repeat.
Now I see what it is supposed to look like - the missing icons on the left side - these are not pictures, but icons for certain functions of the program.
It works perfectly for me is about all I can say.
Sometimes cleaning the cache appears to help in situations like this - I think it is worth a shot.
rm -rf ~/.cache
Or try switching to another theme and icon set?
I set mine to Breath Dark, but Breath light works just as well.