Those are very good questions and I'm hoping that an official answer will present itself.
The answer has previously been that you needn't worry about it but:
https://community.auctiva.com/eve/forums/a/tpc/f/8386099...561028571#8561028571
In the thread above it's suggested by Auctiva that they delete images they "think are safe to delete" but I don't really know.