What browser are you on? Is there any other code around the image?

ETA: I know what the issue is; you don't have an icon on the post. If you plan on never using icons, I can give you a bit of code to fix it, but if you are going to use some eventually, all I can advise right now is to use one on that post. This is a very old theme, and it needs a lot of updates. I'm hoping to redo it in the next six months or so, but I can't rehaul it right now.