Help Making Channel Banner?

[Shortninja66]

I got a partnership awhile ago with AdRev and I want to make a channel banner for my background. I have no idea how to do the pixel-by-pixel coding or what size the picture should be. If anyone has any tips please help, or if you can make a free one for me I can. P.S-

 

[unknown_userr433436365]

In about a week and a half all channels will have the banner, here`s the new template : http://yttalk.com/threads/new-youtube-banner-template-coming-february-2013-png-and-psd.35215/