You can not show a sidebar on the photo page width such a small width. Your medium image is 600 pixels and your sidebar ads are 300 pixels. Your main block to display is around 800 pixels which is about right for how you have things set. Looks to me like your trying to cram in 1150pixels of info in around 1000 pixels. My suggestion would be to turn off the sidebar on global pages only show it on index. You make your mediums smaller etc to fit everything into a confined space.
Your breadcrumbs and other issues as well look to me like your using older templates not the new 7.1 templates.
Steve your vb page is set to like a 1000 pixel width. Yes photopost should be 100% you have that set fine. what I am saying is you can not fit all the info on the 1000 pixel wide display on the photo page its too much info so it scrolls.