Logos should have way to access all images in one's library, organized in some way.
You can do a media search for * in Logos 6 to find all the images in your library, but they won't be organized, so I agree it would be nice to have some organized way to browse through all of them. That would be a monumental task, though, to curate such a list and organize it for browsing (thematically, alphabetically, by Scripture reference?) -- because each person's library is different. The images come from all sorts of places: Logos media resources, atlases, pictures in books, etc. And there are thousands upon thousands of them. But I suppose if they are all tagged with subjects and such, we ought to be able to sort the search results by a variety of criteria to help us browse them. This is currently not possible (the search results are not sortable at all), so that would be where I'd direct Faithlife in making improvements to this.
You could browse images in Scripture order by creating a Passage Guide with only a Media Resources section and then run it on the entire Bible (Gen-Rev). It would take a long time (mine's still going after half an hour and I'm not going to wait any longer to see if it comes up with usable results before posting this), and it would only include images that are part of resources that are of type "Media Collection" which would mean it would omit all images from within books in your library. But at least it's a start.
So, in short, I agree with you that something better is necessary. Not sure how they'd go about this, though. I suppose it could be a process of "indexing" like what we go through for our searches that makes all our images more readily available to us in a matter of a few seconds of search, and that can sort them by any criterion we choose (type of image, subject keyword, scripture reference, alphabetical by title/caption of the image, creator of the image [if available, e.g., the artist for paintings], date of creation of the image [again, if available], and perhaps author and/or publisher of the work in which the image appears).
This would be a cool feature for Logos/Verbum 7 (if not before). But it sounds like a feature Faithlife would enjoy promoting.