Garmin sends me very little information, and a profile picture isn’t on the list. 
I’ve got the Strava picture updates paused because of their low API limits (those are each 1 call).
Related, I notice a lot of photos are ultimately sourced from Facebook. I don’t like that CityStrides calls out to them (this is the last connection to FB that I haven’t removed yet).
I’m a little wary of it, but I’m considering replacing the existing profile photo setup with a manual file upload.