No replies means no clues out there?? I used to be able to do this. Read the thread from a year plus ago here, and thought perhaps one's Facebook sharing preferences are set by doing a manual file export and enabling descriptions/geolocation, but didn't work. Other ideas?
All I've been able to find, I have the same problem, is that peple are entering the description in iPhoto into the filename field and then apparently it works, it appears in facebook as the description. I'm not going to do this as it's definitely not how it should work. Going to phone Apple Support tomorrow and see what they say.
I've come to the conclusion that I'm going to abandon the "official" share button for uploading to facebook, too much trouble. It's been causing iPhoto to crash and also you have to put the photo description into the title field in order to get it to appear on facebook which is useless. From here on I'm going to enter the descriptions in iPhoto in the correct field (descriptions) and use the file->export option and the settings below to export the files which I'll then upload to facebook using the facebook uploader, at least that way I end up with no crashes and I get the description field in iPhoto filled in correctly and the description data uploaded to facebook.
It shouldn't be necessary to do it this way, but it is.
I've no idea what that will do with faces information, nothing I suppose, I'll try it out