Sorry, I realise this isn't directly related to widgets. But seeing as there seem to be image service (IS) specific widgets, I wanted to ask the following question:
Can you build a web app directly on top of an image service? Or do you have to create a web map from the image service first and then create the web app on top of the map?
Duplicate of this thread:
https://community.esri.com/thread/253280-build-web-app-on-top-of-image-service