Some things are NOT okay to repost
For some time, convention photoshoot pictures of David Tennant and Catherine Tate with someone's children have been making their way across social media. I get it, you guys think it is supercute. But it is not okay to repost these. These children are minors. I highly doubt that those are your children. You are reposting pictures of minors to various social media platforms without the knowledge or permission of their legal representatives. I shouldn't have to say it, but unless it is a promotional photoshoot for a show or movie, it is not okay to repost pictures of children. Even if their legal representatives (i.e. parents, fosters etc.) posted them publicly to some sort of social media, it is not okay to take them from there and repost them. The same goes for reposting pictures of any other famous people with minors (and even adult people's fan pictures from any other social media - if they wanted it sent to Tumblr, they would have done that themselves. It is especially disrespectful if you take someone else's photo with your favourite star, cut the OP out and repost it, but I digress).
TL;DR: DO NOT REPOST PICTURES OF MINORS TO SOCIAL MEDIA.
