I found a way to preserve attachments when converting from polygons to points:
1) FC poly ==> create GUID field
2) Attachment Table ==> Create GUID field
3) Calculate each GUIDs for eachtable (polygons and attachments) with the GlobalIDs(polygons) and rel-globalids(attachments) values
4) Create a new text field in the Attachment table called Path (length 100 or more)
5) Calculate the path field like this:
6) Export attachments using this tool How To: Batch export attachments from a feature class to your local machine "C:\atch" for me.
7) Use Feature To Point—Help | ArcGIS Desktop tool to convert poly to points
😎 Add GlobalIDs to the new point FC Add Global IDs—Help | ArcGIS for Desktop
9) Enable Attachments to the new point FC Enabling attachments—ArcGIS Help | ArcGIS for Desktop
10)Use theAdd Attachments—Data Management toolbox | ArcGIS Desktop tool to add the pictures back
Input Join Field : GUID of your point feature class
Match join field: GUID of your attachment table
Match Path: field that stores the path to the pics on your PC
11) Done.