Unable to edit an attribute table of a map image layer in Portal for ArcGIS

Description

A map image layer is a type of web layer containing both feature and non-feature layers as sublayers. When publishing a map image layer from ArcGIS Pro to Portal for ArcGIS, contents in the attribute table cannot be edited, as shown in the image below.

Cause

This is by design. Map image layers do not function the same as hosted feature layers. Hosted feature layers support vector feature querying, visualization and editing while map image layers do not support web-based editing in Portal for ArcGIS.

Solution or Workaround

• Open the saved project file of the map image layer in ArcGIS Pro and make the necessary edits to the attribute table. Republish it as a map image layer from ArcGIS Pro to Portal for ArcGIS. Refer to ArcGIS Pro: Share a map image layer using the default configuration for instructions.
• Publish the web map as a feature layer from ArcGIS Pro to Portal for ArcGIS. Refer to Portal for ArcGIS: Publish from ArcGIS Pro for more information.