Dan, I would think the icons you're mentioning are pulled from the same place that Graham mentions (Book Covers), and are the same ones used for the library and About the Text views, not the image in the module itself.
The image quality is not an issue with every module. Check out the WBC-OT images for the individual volumes, or the front and back cover for Sacred Bridge, the back cover of which can be zoomed nicely to read all its detail. Some Tools (Anchor Dictionary, Eerdmans Dictionary, IVP-Paul and his Letters) don't have cover images in the module at all--and I'm not suggesting they're even needed. My point is just that low-res publisher images should be improved or left out altogether--they're always the first thing I (and presumably others) click on after I open a newly downloaded tool.
Graham, I know it's not a text correction per se, but I'll go ahead and submit one for Semeia and Prisicilla Papers so it can get tracked and perhaps evaluated next time a future update rolls out for those texts. To the point of my original post, I now see this is something a user can't adjust. Thanks for the replies and consideration.