The image controls in reports have a reference to an image file. In classic the reports are processed on the client computer and therefore the file path must point to a file on the local computer. With ForNAV the report is run on the server. This change means that the image file must be on the server and not the client.
If the image reference is invalid or missing, you will get an error message similar to this:
Bitmap file [FILE NAME] in Control [CONTROL ID] not found or not accessible
This error is fixed by making sure that the image reference is valid on the server.