This demo file contains two simple bookmarklets to reveal whether CSS background images are being used in an inaccessible way.
One bookmarklet outlines elements that have a background image set. The other bookmarklet removes all background images.
The idea is to see whether any of the informational images on the page have been set as CSS background images instead of foreground images. This is an accessibility problem, since CSS background images can't have alt text to explain the information contained within them.
Install the bookmarklets by dragging the bookmarklet links from the demo page to your browser's bookmark bar.