Can I use a custom Image with lat/long instead of x/y in arcGIS (Javascript SDK)? Can I use a custom Image with WebMercator spatialReference?

I’m using ImageElement and MediaLayer, such as in this example:
https://developers.arcgis.com/javascript/latest/sample-code/sandbox/?sample=sketch-3d

to upload a png as the map. In the example, they use x and y coordinates. I’m wondering if it’s possible to integrate latitude and longitude into the image instead?

If it’s not possible to use lat/long instead, are there util functions available to convert x/y to lat/long for different spatialReferences? The only one I could find was in WebMercatorUtils (but I don’t think I’m able to use WebMercator with an image/ImageElement)… which leads me to my next question:

Also, is it possible to upload my own image/ use ImageElement with the WebMercator spatialReference? When I set the spatialReference to WebMercator, my custom image disappears and I see a round globe with no map/images, which I guess would make sense since WebMercator is for a round globe..

If it’s not possible to use WebMercator with my own image/ImageElement, is there an easy way to convert points between 2 different coordinate systems? I think the one in this example uses NAD1927 lat/long (wkid 4267)

Thanks so much for the help!