The Edit widget on AGOL supports attachments. This feature appears to be missing in the developer edition. Does anyone know when it will be available?
Apparently, they are supported but there is some very odd behavior. The editor and map have to be on the same page. Perhaps that is by design, but we wanted to place the map on a page and the editor on another in order to maximize screen real estate on phones. I worked around it my placing two maps. The one on the smae page as the editor is placed below the editor so you never see it.
This is by design for performance consideration. Map widgets on other pages will not be loaded.
So the Edit widget should connect to a Map on the same page.