(io.github.celluloid_player.Celluloid:3448): Gdk-ERROR **: 12:00:45.595: Resource path /org/gnome/arc-theme/assets/titlebutton-minimize-dark@2.png s not a valid image: Unrecognised image file format
Trace/breakpoint trap (core dumped)
I’m fully up to date and I haven’t had any issue with Celluloid, it still plays videos just fine. Perhaps if you haven’t already try a system reboot and see if that makes it difference, sometimes that is helpful to reload packages after they’ve been updated from time to time. Also, it may depend on if you’re still on Xorg or Wayland, as Wayland does tend to have some issues.
if you use the adwaita or adwaita-dark theme, does the error still happen?
Edit: I’ve testing open Celluloid on Adwaita, Adwaita-dark theme, Yaru-gtk-theme, pop-gtk-theme, and arc-gtk-theme and it is only an arc theme issue. All those themes open up Celluloid just fine, but whenever I use any arc theme, it won’t work, so it’s not an Arch issue so much as it’s an Arc Theme issues, so you’ll want to file a bug with the arc gtk theme here:
Edit2: just a bit of a warning, I don’t think Arc theme fully supports GTK4 yet, and Celluloid is partly/fully built on GTK4, so you might want to switch to one of those themes I’ve mentioned that support GTK4 or wait for a fix from the Arch theme developer.
No worries, happy to help. If you want to try to keep your Arc theme, you could try uninstalling Celluloid and instead try installing it as a flatpak, and see if that works as a temporary workaround as well.