I am trying to add dynamic images to a map with data driven pages. I have found the following resources:
1st. Enabling attachments—ArcGIS Help | ArcGIS for Desktop
2nd: Adding attachments to features—ArcGIS Help | ArcGIS for Desktop
3rd: How To: Add dynamic images to a map document with attachments from Data Driven Pages
I can get through all three tutorials, until I get to 3rd.6, which tells me to select "Attachment from data driven pages". I cannot do this, as the option is grayed out. I have tried on 10.3.1(standard) and 10.5(advanced), multiple times for both. I don't know what step I am missing. I have added only 2 images to the attachments for testing purposes. Do I need to fill out the whole table for it to work? What am I missing?