Fooled at First Sight

When you think a girl is really hot initially, but then you see other pictures of her that aren't as flattering. Your opinion of this girl deteriorates and you sometimes even question her beauty.

Also can be referred to as Fooled at First Boner.

"I used to think this girl was very hot, but after seeing unflattering Instagram pictures of her, I no longer think much of her in the looks department."

"Seems like you were fooled at first sight."