Adding a daily image to add value to my site, and . . .

I currently have an index page with a Google PR of 5/10. That page features a daily image which changes automatically via php script off of my web host's server. I have this daily image to hopefully bring visitors back every day and add some creedence and value to the page. Later I launched another web site, placed AdSense throughout the site and wonder if it will do the new site any good by adding the same exact daily image script to the new index page? I.e., it links it to my other already 5/10 ranked homepage I hope would help elevate the new URL in a faster, more appropriate and "organic" way. Basically, I am hoping by having my "custom" tailored php script on this other site, it will add some PR value to it. Or, should I simply include a text hyperlink on homepage of NEW site to already ranked 5/10 site? Feedback appreciated.....