It would be down to an action group that imports all the various covers where the first action replaces all existing covers so that there is just one, the new one left and then follow the other actions that do not replace but add pictures.
I would like to add that the modification of a cover type with an action would also be nice.
A fair number of podcasts regularly feature the cover type "other" which I would like to set to "Front" - don't know why the publishers can't do it right but that's the way it is. So I have to do it frequently, manually.
I posted a suggestion in the German part of the forum: