Did you check out access rules of the entity which is generalised from System.Image to view the dynamic icons?
Dear David,
For Dynamic images (associated with a System.Image entity), the generated URL might be relative, missing a required protocol (e.g., https://), or pointing to a location the web application server/client cannot access due to permission issues.
You can check the below points :
1.Verify the Dynamic Image URL
2.Ensure Correct Path Configuration
3.Check Server-Side Access and Permissions
4.Confirm Image Association
Regards,
N.Mohamed Rasik