Thumbs.db is the ThumbsPlus thumbprint file. When you open ThumbsPlus in a folder that has images or other files ThumbsPlus can display, it creates thumbprints and stores information about them in a file in that folder named thumbs.db. I don't know any programs other than ThumbsPlus that can open these files and I doubt they contain any information that is useful to anything other than that program.
I imagine the .info files are information text files. I've seen .nfo files but not .info, so I'm just guessing. Hope this helps.