Colors: whatever goes good with the pictures
Size (in pixels): 500x300
Things to avoid (what you don't want in your image): Just try not to make it all bright and ugly looking.
Effects: some cool X's, stars, skulls, or whatever would be really nice.
Extras: I would also like a border, and an avatar to go with the blend. Thanks so much to anybody that wants to help me I really appreciate it.