In my installation (v20220308, MacOS 12.2.1) some icons do not show up in the preferences editor, in particular the checkboxes/radios. When I try to assign these icons in the appearance editor and select an image from the pixmaps folder, I get an error message "… could not be loaded as an image". Same if I choose any other PNG from any folder outside the package. Attached image shows appearance of checkboxes/radios as I see them.