Suddenly my friend turn her back to me

I really don't like when a "friend" of me suddenly put out a picture of she and my boyfriend (my boyfriend is her ex) kissing.. And it's like ... Over a half year since they broke up. But she is jealous on me because i'm with him... (think she still loves him or anything like that).. But anyway, she post the picture of she and him kissing today with the text " I love you my boy <3 , Miss you </3" ... And i was like, wtf ? What's the point ? And when i asked her to remove the picture because i didn't like it and i think it was just stupid to publish that picture now, she just said " i don't need to remove it just beacuse you want it, it's my choise what i publish on facebook and not. You got no rights to complain about it" ...
And now a friend of her texted me and told me i should stop caring about what they did and all that stuff.. And they two and I was soo good friends before... Before my boyfriend got in the picture.. And i really don't know what tot do about it...