My iphone is already pwned and has the steve image and pineapple start up image. If i wanted to have the new images such as the multicolored apple could i put them in the place of the pineapple and steve and then pwn my phone again, will this do anything bad to the phone or can it be pwned more than once to get new images etc.

Have a look at this thread
http://www.hackint0sh.org/forum/show...=rainbow+apple