ok I think I know whats up. your google account info might be taking default over the facebook picture. I tried it with one of my contacts that had both a gmail address and a facebook account. I defaulted to the google pic until I deleted it.
scroll down a little after you delete the image and you'll find the facebook pic. click on that and it'll give you the ability to choose that one.
Try that out
Alright.. I think I'll try it tomorrow. Or later today, technically.