If you mean to change the basemap imagery, that would be a no (see Scotts respose). If you mean have points (from xy coordinates) or polys (from AGOL layer) then you could tie your pictures to a URL in your table. However the source would have to sit on a public server. I haven't found a way of displaying pictures on a site requiring credentials, such as sharepoint. That's limiting because we don't want to publicly share our documents for internal Power BI dashboards. BTW the AGOL is a fairly cheap cloud document storage solution, and if you share globally its as good a place to store docs/photos as any. It's unlikely (though possible) that someone will discover your docs. We use AGOL for attachment storage and link it to features on the map. its a little clunky, because we haven't figured out how to read the REST features directly into Power BI (if that is even possible?), so we synch the table with Sharepoint every so often so that the feature table is available to Power BI and displayed as just xy points on the map (they are polys in AGOL, but we don't want to publicly share them).
