Greetings,
I am creating an app that contains a Gallery populated from a Sharepoint list with a Person column from which I get, among other information, the user's picture:
ThisItem.Helper.Picture
This works perfectly when viewing the App in a browser:

However, when embedding the App as a MS Teams tab, the image boxes show empty:

I am at a loss as to why Teams would not have access to this piece of user information or where to look for error codes. Any advice would be greatly appreciated.