I had a look at that page using IE8 and Windows 7 through Browserstack and I'm actually seeing the gallery images in two columns, not one. What operating system are you running?
Are you using WordPress's built-in gallery functionality to create this gallery?
As I mentioned earlier, Coraline is a modern responsive theme and unfortunately IE8 really isn't great at rendering sites built with mobile-first techniques.
To rule out a theme-related issue, could you try switching to a default theme temporarily, like Twenty Thirteen or Twenty Twelve? You may need to reset any widgets or theme-specific options so you may want to make a note of them. Alternatively, you could set up a test site - always recommended in any case - and try it out there in IE8 instead.