Help me with a background please

[My_Little_Dashie20 14]

I need your guys help, i'm trying to find a good background for my profile. All the ones that i've tried are sucky looking, they're too small and they look bad when they're multiplied. I want a background that EXACTLY the max they require, if anybody can do that I will draw their OC. I'm not much of an artist but I will try my best. Let me know if you can help. P.S: The background has to be Rainbow Dash because she is best pony. 

[Leafeon 2,702]

Just pick a picture with her off to the side, then resize it to be 1600 x 900 pixels then save it as a small (Under 255kb) JPG file.

 

Just as a note, if you have already used a certain file extension, it will take a while to change.