We are happy to share that this is in testing, and expected to release in the next quarter.Gerard commented
Please merge https://office365.uservoice.com/forums/264636-general/suggestions/32017660-teams-picture (736 votes) in to this idea as well.
This issue has been listed as known/discovered since March 1st 2017, the "workaround" listed is to vote on this item, but clearly this has no effect whatsoever, because here we are, two years and 9 months later, and it still has not been solved, there has not even been an update for 1 year and 4 month. And Teams is supposed to be an enterprise-class product? I would call this a joke, except that it isn't funny. There must be some very incompetent people working on this, who don't care about customer feedback.