Problem with graphics shifting

[Jack the bookseller]

My website www.secondhandbookshed.com has about 20 main pages each using lightbox to display 16 thumbnails per page normally. Under each thumbnail I have put a 'more info' button (4 per line) wich should line up. When uploaded they often shift up or down out of line. I thought I had located the answer to this on the forum ie 'in BV go to : tools/Options/Publish and check the box that says 'Use page name for prefix' I did do this and then checked the newly uploaded pages and the problem appeared fixed. However on checking a week or two later some of the 'more info' boxes appear to have shifted out of line again. I emptied my 'cache' and checked again however they were still out of line. You can see the problem on various pages using the navigation bar at the bottom of the page. Can anybody help please?