Making a wallpaper?

[Ryum]

I have found things like
http://www.ehow.com/how_5952261_crea...wallpaper.html
which outline how to do it, but what seems to be missing is how to make it so your phone either uses a different wallpaper or a different picture when you slide open the keyboard.

I guess I am assuming there is a way to do this because most pictures I have in mind won't translate well when turned and stretched like that. If that is not the case that's cool, just wanted to check.


One last thing the resolution for the TP2 is 480x800 right?
and what size would you crop to for a wallpaper that will span 3 screens?


thanks