copy that picture and PhotoShop it. make it transparent! or, if you don't wanna mess up, you can open a .theme for winterboard. Or if you're already using a theme in winterboard then you should add a folder named .../yourtheme/Bundles/com.apple.springboard and add a that transparent image. Name's gotta be SBBadgeBG.png or else it won't work. Respring...
ohh the badge number..? oh haha. I did't see that. Well. I don't know about that. You should use my badge then. It's real simple, looks cool on any theme...
Send big files the easy way. Files too large for email attachments? No problem!