This is super cool! Adding on to Chistina_Appleby's question from yesterday to see if you'd share a little more about how you did this? I'm assuming you hosted the images somewhere, embedded them in an excel sheet which was then published as a table to ArcGIS Online, and then pulled into the app? Definitely interested in how you exposed each image to the internet, and whether I'm on the right track with the rest of it.
Very slick implementation.