In my opinion it doesn't look good to use photos as homescreen background. Simply, because of the huge icons you can't see heartly anything of them. The default background images are nice, but there are none with studs, so it was obvious to make some.
The following images are optimized for the native iPhone 5 Retina display with 1136 x 640 pixel. Please note, for testing the best result, the images are made with low compression. I don't know, if the huge images will slow down the performance.
The image should be unobtrusive, but the stud should easily be recognizable. Let's start with black & white.
|The Shadow is
generated by iOS
Eh, come on - monochrome is nice, but LEGO is more colourful, isn't it?
Next try with a yellow baseplate and different sizes
|Yellow Baseplate 10
||Yellow Baseplate 12
||Yellow Baseplate 14
|Yellow Baseplate 16
||Yellow Baseplate 22
||Yellow Baseplate 26
Want to try them all? Download them here