Weird thing going on with redshop, I've seen this before with Music collection, both of them use dynamic image sizes, some times they load and others they don't. I'm working on a mockup site for a customer and I don't want to show her this site if this is going to be a issue for her. You can see this in action here:
http://8balla.com/index.php?option=com_ ... Itemid=333