Nostra, I don't expect you to know how raldo has coded his plugin (I certainly don't!), but I would like to ask on his behalf...
What is the method for addressing/selecting one particular image associated with a movie? In particular, is there a way of selecting the poster that has been selected ("paper clipped") for display when there are multiple posters? MC can handle only one "cover art" item, and this is the obvious one to import.
From my testing of the plugin, I can only guess the issue of multiple posters has not been addressed. Where there are multiple images, it might select anything—usually a poster, but sometimes a screenshot or cover. I don't see any pattern to this, so maybe it's getting image with the highest or lowest index number. The only way I've found to change the image it's getting, is to delete the image, run it again, and hope it gets a poster. If I re-add the "offending" screenshot or cover again, it may be selected again, or it may not.
Looking at the database tables, I see there's a field for the image type. So I guess the obvious solution is to restrict the selection to posters. It would be desirable, however, if the specific poster selected for display in PVD could be selected. I couldn't determine how this is recorded in the database.