Chicago Plus: mogrify doesn't work

In chicago plus, while applying the theme, mogrify doesn't do what its supposed to

```
mogrify: no decode delegate for this image format `' @ error/constitute.c/ReadImage/746.
`Traceback (most recent call last):`
File "/home/blenk/git/chicago95/Plus/PlusGUI.py", line 1223, in install_accept
self.install_theme()
File "/home/blenk/git/chicago95/Plus/PlusGUI.py", line 1248, in install_theme
self.theme.go(cursors=self.install_cursors, icons=self.install_icons, wallpaper=self.install_wallpaper,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/blenk/git/chicago95/Plus/pluslib.py", line 158, in go
self.generate_theme(cursors, icons, wallpaper, sounds, colors, fonts, screensaver)
File "/home/blenk/git/chicago95/Plus/pluslib.py", line 279, in generate_theme
self.convert_colors()
File "/home/blenk/git/chicago95/Plus/pluslib.py", line 1273, in convert_colors
self.change_asset_colors(self.folder_names['theme'],
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/blenk/git/chicago95/Plus/pluslib.py", line 1820, in change_asset_colors
subprocess.check_call(args)
File "/usr/lib/python3.12/subprocess.py", line 413, in check_call
raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '[b'/sbin/mogrify', '-fill', '#000000', '-opaque', '#000000', '-fill', '#a09cb8', '-opaque', '#dfdfdf', '-fill', '#384080', '-opaque', '#808080', '-fill', '#5864b8', '-opaque', '#ffffff', '-fill', '#84a3d2', '-opaque', '#c0c0c0', '-fill', '#ffffff', '-opaque', '#FFFF00', '-quiet', '/home/blenk/git/chicago95/Plus/Vaio1_Chicago95/Vaio1_Theme/gtk-3.0/assets/throbber']' returned non-zero exit status 1.
```
After inkscape does its work with the icons, it just ends up there