sonjay - 3:31 am on Dec 10, 2012 (gmt 0)
If it matters he usually use a "high contrast" theme.
That might matter. Are the missing images background images? According to the WebAIM blog, "CSS Background images are often used on websites in place of true images, especially for small icons or for elements that are repeated throughout the page. These images are typically hidden in High Contrast Mode. The good news is that this means that decorative background images will usually be hidden, simplifying the visual layout of the page and potentially enhancing accessibility. The bad news is that CSS images, including CSS sprites, that convey meaning will usually be completely invisible."
I believe that a link to the WebAIM site is permitted here. (Or if it's not, I think it should be.) You can find the info about the background images and high contrast mode here: [webaim.org...] -- scroll down to the "Background CSS Images" section.