Boyfriend liking other girls pics

How would you react/feel about your bf liking other girls pictures that are sexy? I saw my boyfriend has liked a few pictures on a girls FB, I’m kinda upset with it. I’m not gonna post her pic but it was of her in shorts n Croptop with smoke around her in the background. He doesn’t like my pics. He barely even finds me attractive in person and him liking pics like that just makes me feel worse and that he doesn’t like me.