I was playing with the New ArcGIS StoryMaps and got bummed out on the first page. Maybe I'm doing it wrong, it is a whole new experience, but it seems there is no way to reference an image via its URI. Instead, I have to upload the image to be hosted on, I assume, ArcGIS Online which will cost credits. No bueno. I'm already paying AWS for an S3 bucket so I can use my images elsewhere. I don't wanna upload images. Is there a way for me to just reference my image's public URI?