Trying to customize my blog

Well, I'm in the process of trying to customize my blog.  I'm going to have to redo some of the links that I had before, but I'm going to do it a little at a time.  I've checked all of the FAQ's to see if anyone posted an answer for this question, but so far no dice.  Does anyone know how to make the image page element tag allow you to put a bigger picture up?  I just want to enlarge the one already on there, but I can't find out how to do that!  I'm just a little frustrated, so any help would be much appreciated!:)