I would like to have a way of identifying Add-in instances once they are inserted in the document.

My addin adds a picture in the selected part of a PowerPoint document. At the same time I also add some persistent data using Office.context.document.settings.set

Is there a way to specify the name of the picture within powerpoint?
When I unzip the pptx I see that my persistent data is on the webextensions.xml but when I look at inside the slide folder, for instance slides1.xml all I see is the pictures but I dont have a way to associate the pictures from sildes1.xml with the attributes stored on webextensions.xml