If you remove images from the Image Library in FF3, the LAST one leaves a "shadow" (see attached picture) and there's no way, at least to my knowledge, to completly clear that list.
Yes, that does seem strange. I will have to test it out here to see if I can duplicate it.
Another problem that I see with your screenshot is that the text is missing from the Toolbar. Check out my screenshot that is attched. Do you ever see the "Add Image", "Remove Image", etc... text in your Image manager Toolbar?
Yes, I get all those options, but I get what you see when the "ghost" image is there.
EDIT TO ADD: Let me correct the above, I did see the text, now I don't, I tried creating a new project, no text after the buttons.