I noticed a couple of places where images have also disappeared because they're in td tags with the alt1 class and undefined width...
- The Ivrnet logo at the top, and the "thread status icon" cell (the leftmost cell on the topics page) are both in cells with the "alt1" class but no defined size, so they disappear too.
- You could fix that either by changing the class on those cells to "alt2" (which seems to look exactly the same as "alt1"), or put a defined size on the img tags or the td cell.
I don't know how much control you have in editing those things.