Could this check be because wx.Bitmap crashes (in C, outside the interpreter) with an invalid path?

@DietmarSchwertberger

It doesn't, you get an exception in Python (not in wx.Bitmap(), which just returns an object with IsOk() == False, but later when trying to add it to the toolbar) and a nice error window.

Note that the qt5 backend has nowadays a similar methd icon() In particular this handles color conversion of icons for dark themes, which is not yet implemented in the wx backend.

Note that for easily checking dark theme we need wx.SystemAppearance which will only become available in the yet to be released wx 4.1.

I'm therefore inclined towards keeping the method.

Fair enough, changed this to just strip out redundant error checking (per above).