When i view entries from a sharepoint list it may occur that this list contains a picture column. That means this picture column contains a link to a picture. Usually such a picture is stored in a sharepoint library or a picture gallery.
Right now it seems a powerapp can only view a picture from a sharepoint list if it was from an external source (internet) Pictures from any library are not shown in the power apps. They are displayed properly in the sharepoint list but not in the powerapps.
Please enable powerapps to display pictures from sharepoint libraries!