You like to remove covers.
I like to include 'alternate' (other edition) covers. This is probably from wanting to have the cover on the copy in my Dead Tree Library copy.
You do bring up good points about the difficulty of locating:Placement, type (content) of image,
Maybe a Report: Count of Images( broken up by size groupings:small, probably Logos, dingbats; Medium: Maps, charts or half covers; Large: Covers, titlepages )