Being a guy who loves long hair on girls I'd say that you look a 1000 times more beautiful in the first pic than the 2nd (which, for me, isn't attractive at all). Growing your hair out would make you irresistible to me :P So i'd say go for it. But that's just my opinion and many people may not like it.
I LOVE the cut on the second pic. You look banging and I would kill to look that good with short hair. Personally I have really long hair but I've always wanted short hair but I'm sure I'd look stupid so embrace how awesome you look with short hair. by the way the color looks awesome too.