As the topic stated, I was wondering if you can store multiple pics on the HDD to be able to use them like the factory preset back splashes.

Only if you have access to the hard drive connected to a pc.

See my detailed post here:

http://avic411.com/index.php?/topic/14564-z2-z3-how-to-upload-backgrounds/page__hl__background__st__15

thanks Garret. you are definately a wealth of knowledge.