when getting new themes on the torch from bb app world ive seen the screenshots and they have pics on the background those are just generic pics correct i can use any theme with any pic of my choosing correct?
Yes.
I have tried a few themes and always had problems with all my icons getting pushed out of order, and search functions not working. But that could just be me.
Most themes allow you to change the wallpaper background of the home tray and some offer the ability in all trays. If you are curious about a particular theme then ask in the Themes section.