You know...call me naive, but these things called computers and servers and all manner of tech stuff, have been known to hiccup on occasion.

Maybe the person just happen to post during a reset or something...in the few seconds when the system preferences had not yet been fully applied?

Or maybe that image restriction had been inadvertently left off in that one forum?

Who knows? Who cares? Not like the person posted a pix of Jenna Jameson sucking a golf ball down forty feet of garden hose or something.