Started seeing this every now and then on v251. Previously I don't recall seeing this. It only occurs when a profile picture has issues loading and typically is temporary; the error is removesd once the link resolves. Before it's resolved, it can be a hindrance.
I support apps being more verbose and error messages but in this particular case, I don't think the error message is necessary; if the a profile picture link doesn't resolve, so be it. Maybe on an user profile page, it may be more of a consideration.
Thanks for the report, you're right in this scenario it shouldn't be trying to display an error message. Will be fixed in the next release (tonight). Cheers!