forgetting to change it from RGB when painting images or saving renders.
This makes more sense in the new alpha pipeline, renders no longer contain an
alpha channel that does not match the RGB channels, so saving files as RGBA
should give the expected results when opening them in other applications.
default settings in the startup.blend without having to actually save and embed
the file, which can be a tricky process and is problematic in branches and
patches.
This function can be emptied each time a new startup.blend is committed.
