My mom and dad in law favor their other grandchild MUCH more than our child?

My husband's brother had a child in 2008, she is my mother and father in law's first grandchild. (I'll call her Jane) About a year later, my husband and I had our daughter. My mother and father in law, as well as my husbands other siblings, favor Jane MUCH MUCH MORE than our child. I understand she is their first grandchild, and the first baby in the family, but it is ridiculous. They gush about her on Facebook, they post dozens and dozens of pictures of her. And they do love my daughter as well, but they make it so obvious how much more they care about Jane and it hurts, a lot. I don't know if I should say anything or not? It is incredibly hurtful. They babysat Jane for about 5 days a week during her first year, because her parents both worked full time. I am a stay at home mom, so they never babysat for my daughter like that. I think that has something to do with it, but am I right in feeling that is no excuse, and it is still unacceptable? I will definitely say something if this is still going on once my daughter is older and able to understand and see how much they favor Jane. I'm not going to allow Jane to be hurt like that. But should I say something before then?