There is a bug, or a set of bugs, such that attempting to load a large image in Firefox causes Firefox to do something that hoses my X server badly enough to hard-wedge my graphics card, freeable only by a reboot. Not to put too fine a point on it, this is fucking annoying, because I don't know before loading it whether a URL contains an image big enough to trigger the bug.
Hmmmm.... I wonder if this could mean some recent change broke compatibility for the Image Zoom extension?