[unboggling]

Or, to start from scratch (I think, not sure about all the images getting deleted this way), save out the text under the cover images to a temporary text file. Click anywhere once in the edit sig box where you enter text. Keyboard Command A (Control A on Windows?) to select everything. Hit delete key. Preview Sig. If that doesn't also remove the images (more globally than removing just one as in pdurrant's post), I don't know what will. Save Sig. Start over, using just the images you want to be there, and paste back in your text underneath.