Well, as the core of my builder code was pretty much there, I decided to see just how big the resultant set would be (I'd only focused on single screenshots before without boxart). Amazingly it came out just shy of 20,000 images and around 700mb in size even with lowly RLE! Not sure how many would allow that much of their HD space for screenshots alone on their rigs.
Anyway, this is just a first cut as I still plan to do the dithering and other packs, but this should get things started. It's now in my upload folder on the FTP for those that would like a preview (271mb - TinyLauncher-Screenshots-v0.1.7z).
Many thanks to Frode Solheim and all of his contributors. The Openretro database is an amazing resource for the community.
Oh, and we must let Gibs know certain files that seem valid (i.e. they load with MUGiff on both an emulated A500 and A600), but they cause a guru in TinyLauncher. For example the 1st Division Manager boxart seems to give problems for some reason.