Unable to view images on the internet.

One of my users, when he is on the internet, is unable to view photos on web sites that he visits. He can go to the sites and view text perfectly, but where images are he sees only a small box with an “x” in the center. He has deleted all temporaryinternet files but the problem persists. In some cases, when he clicks on the box the image will appear.. Are we missing something? Is there a setting that has become corrupted? Is it an issue with the computer, or with IE??