Audrie Gordon from the PowerApps team digs into the Shoutouts template to show you how the Add Media ("Upload Photo") button works. That upload photo button is actually an ungrouped piece of the "Add picture" control (found on the insert menu). Learn more about this in the references below...
References:
https://docs.microsoft.com/en-us/powerapps/controls/control-add-picture
https://docs.microsoft.com/en-us/powerapps/add-images-to-excel
