I must be xcomics challenged because I can't add a new comic and get it to rotate as the comic changes on the original site?

I tried adding Peanuts, and don't seem to have the right code in order for the comic to change daily. Here's what I have in the PHP code box:


I'm sure it's something obvious, but for the life of me, I can't get it to work. Any suggestions?

Thanks in advance

Kristine