Well, depending on how both of you guys broke up is something that should be given much consideration before making any decisions on whether your ex was even supposed to react to any of your pictures or post on social media probably on Facebook. Now, if you guys broke up in a very sad and bitter manner, then it's not right for either of you to still keep an observatory eyes on each other's lives and activities on social media (Facebook) unless either of you are looking an opportunity to make up and resume the relationship from where you both stopped. But if it's something that is not serious which led to your break up, probably it was something that neither the both of you had control over, then it's only normal that either you would still be keeping tabs on each other.