Hello,
I've upgraded TFS 2013.4 to TFS 2015 RC some time ago. Since then, Team Projects' users are randomly "loosing" their profile pictures. It's like once a weeks someone's picture is changed to default gray icon.
Additionally, it is impossible to set the picture back using Google Chrome. It is sometimes possible using Internet Explorer, but not always.
I cannot restore the profile pictures using TfsTeams.exe anymore.
I reckon this post is more of a bug report than an actual question, but I couldn't find any "Report a bug in TFS" link, so here I am. Hopefully the TFS team will have it repaired until the 2015 release :)