I’ve tested your website in IE11 (screenshot) and IE10 (via Browserstack, screenshot), they both seem to be displaying the images correctly. Could you please tell me which version of IE you are using to test the website? Thanks!
I’ve dropped IE8 support for all themes since the beginning of 2014, following ThemeForest’s lifting of this requirement. What you can do, though, if you want the website to show images in IE8, is transfer the background CSS rules into the theme’s “ie8.css” file, like this: