My boyfriend constantly likes other girls selfies?

[T]

My boyfriend is constantly liking other girls pictures on Instagram and Facebook, and all the pictures are the girls "selfies" and there's one girl in particular, he likes every single one of her selffies. We are both 19 and have been dating for 6 months. It really bugs me. I don't really get jealous, but when I see that he likes all these girls pictures it makes me feel really upset and insecure (I generally am a very insecureerson anyway) I don't feel the need to like other boys pictures but I do because I feel like I have to because he does it. Is it worth saying something to him or am I being way too sensaitive ?