the_importer: bump I guess
PookaMustard: The images are stored in "C:\ProgramData\GOG.com\Galaxy\webcache". You should have a bunch of folders ending with overlay, one common, one titled just 0, and one that's simply a long string of numbers, this is where the images are stored, at least for my end.
I don't know about the specifics of the tags and preferences, though.
Ya, I found that out earlier this evening while digging around, strange place to put them. That being said, I also found out that it's more or less useful to back them if you ever modify them because it would appear that anything you replace is synced on GOG's server.
I installer Galaxy 2.0 on my old laptop the the couple of images that I replaced from my Desktop are on my on my laptop now as well as all of the tags for my GOG and Steam games. At first, I figured that the tags in 2.0 would be independent since they were not the same as Galaxy 1.x /GOG.com website, but now I think that once 2.0 is public, that the user's purchased game section on the web site will be the same as the 2.0 interface, tags and all.