The Stack Exchange API supports (read-only) access to Stack Overflow for Teams; see the documentation. Since Teams content is private, images aren't uploaded to imgur.com, but instead hosted on the Teams server. The resulting URLs look like this:

https://stackoverflow.com/c/[team name]/images/s/[guid].png

and can only be accessed via the browser when you're logged in. It looks like they cannot be accessed via the API; could this feature be added?