Okay ima post this again! My BF took a pic of a group of friend & a ghost appearred! Wtf does this mean:?

Okay well again I was at a party this Saturday & my BF took a pic of a group of friends. I noticed a face appeared under my friend all the way to the left side.. Wtf does this mean.. Im hella trippen out. The pic is attached to my profile but u may have to zoom in to see. Its just a face with black eyes & the eye have a glare from the flash or something. But i have no idea how it got there, that face was not there when we took pic!!