It depends on the girl and depends on the tat. Honestly, in most cases if a girl was cute without them, she'll be cute with them. Similarly if a girl wasn't cute without them, she won't be cute with them. So I guess they don't make you more or less attractive in my eye. Just make you, you.
I personally don't mind when a girl I'm interested in has a few tattoos if they look good and actually have meaning behind it. But it becomes a turn off for me when the girl has more tattoos showing than bare skin.
I don't have any tattoos but am thinking about getting a couple... And I don't give a sh*t what guys think! I'm doing them for me. Just like different girls dress different ways or have different opinions, a guy will like you for who you are and if some guy doesn't, then he's not right for you or worth your time! As long as the girl is happy with how herself and her tats I think it will look amazing :)