Well, Master Pages are essentially templates for a page layout that you can set up then link each new page back to it so that your graphics, text, etc. are placed consistently. Then, when you get to each new page, you double click the existing placeholder and just dump your stuff in.

My first inclination (without looking it up) is to set up facing master pages with your full-bleed graphic placeholder and then add a box on top of it to hold your automatic page number. But, as I said, all my InDesign stuff is at home so I really can't say for sure.