Do you have any type of extension installed that blocks pop-ups or something (which may have gotten set to block images also?)

Since this is a strange problem, some sort of broken extension is the only thing I can think of.

In Tools, Extensions - you can right click, and DISABLE them. You may want to go through and disable some of them to see if any of them are causing a problem. (Then you can renable them after testing if they were not the problem.)