Lady In The Corner Ghost Picture

Melissa G. sent us this ghost picture which looks similar to a double or lengthened exposure. But if there was no one there who looked like this, where did the face come from?

"My friends and I were in old downtown Seattle (aka Belltown) last year. We went to an old club and had a good time (as made obvious in the picture). We later noticed a face on the left side. It was creepy - no one was around like that. It was taken with my friend's Kodak digital camera (don't know the model though). There was definitely a flash. Anyways, we aren't sure if there is a reasonable explanation, but thought we'd find out."