Failed to load resource:404 image

You have a rule in your .htaccess that prevents access to your images for anyone sending your domain as referer. Disable the referer on your site, and all images will show up.

Remove that rule.

To get this on topic: Whenever you have any problem where you don’t know how to debug it –disable all plugins, switch to TwentyEleven and use the default .htaccess. Then re-enable each part step by step until the problem comes back.