Random Wallpaper Changer Using Tagged Images?

I wish to make a wallpaper changer that can select a random wallpaper from a given directory and sub directories. I'm not asking for code at this point, I'd like a reality check to see how hard this could be. I'm still quite a newbie at VB so I just wanna check if what I'm thinking process wise would work.The basic thing I'd like to do is have it pick one picture out of a given dir and sub dirs. Then set it as the wallpaper. I'd like it to be resized if larger than the desktops resolution to fit inside it, no stretching cropping or stuff.

That's the simple things I'd like it to do. Unfortunately I have dual monitors so it'd have to pick two wallpapers, resize each one independently, stick them together, and then set the wallpaper. I'd also like to make a kind of simple database which would have the name of each pic and two values with it. I'd like a value to mark if it's been used already which would be reset when all pictures have been used. The second would be a simple tag. This way i could have all car wallpapers listed as tag 1 and all non-car wallpapers listed as tag 2. Then I could chose whether to use all or only tagged wallpapers.