Something similar was reported earlier and it had to do with using FireFox 16. If you are and haven’t upgraded recently, you can do so here http://browsehappy.com/ or click the update button in Firefox.
If you aren’t using Firefox 16, please let us know what browser and version you are using.
I’m having the same problem with the ‘Columnist’ theme. Sometimes the photo appears in the heading graphic above each column, and sometimes in the text. I’m using Safari 6.0.2. Is size anything to do with it?