graphic issue

[spaLOGICng]

I have a report that has a graphic field which based on a value in an unbound field. The code works.
But when I put that code on open of the report, no value get put in the unbound field. If I put that same code in a command button, it works fine.

So, I'm guessing some kind of time issue?

Here is the code: If [Mdid] = "ABC123" Then [backgroundpath] = "\\Reportbackgrounds\ABCreport.png"

Work with the Print Event and Format Event for the section