Short story.....I got my son the Atrix 4g the other day and he's got a nice wallpaper on it that I wanted. Using the file explorer I looked around until I found it and transferred it via bluetooth to my phone. So I tried to do the same to get the wallpaper you want off my A2 but because in stock form we don't have access to the phone storage I was unable to get it
But a root method has been found for the A2 so as soon as I grow a pair and give it a go I'll hook it up for you since I'll be able to gain access to that storage area.