The Top Margin of the Screen

Greetings All!

Like many of you I use various pictures as wallpapers on my Diamond. As I've tried different ROM's I've noticed that the top of the wallpaper images don't always start at the same vertical location from the top of the screen. Some start at the very top, some maintain some sort of a margin. This means that the top bar doesn't always overlay the same amount of image between ROM's.

Is this something configurable? Just a quirk? Thoughts? It's not differences in image sizes or what not. I've tested the same images on different ROM's. As the prefix indicates, I always use Sprint ROM's when possible.

As always, thanks in advance.

Cheers, Henri