Image overflow problem

Hi guys
Just finishing off my website, realised it works pretty sweet in most newer browsers besides Internet Explorer for Windows.

The problem is in my gallery and mods section, where the thumbnail images seem to overflow past my right hand menu. This also extends my main content box and makes it look ugly. Any ideas how to fix this with CSS? It works fine in IE for my Mac but not under Windows.

Gallery: https://www.psychofett.com/?page_id=2
Mods: https://www.psychofett.com/?page_id=4
CSS: https://www.psychofett.com/wp-content/themes/psychofett/style.css

Any other advice or tips would be appreciated also.

Thanks for your time.