How to choose and set a report header image at runtime

I'm new to the SSRS product. I have 20 reports one for each of 20 different departments I been asked to build a single report to replace the 20. I easily accomplished this by adding a simple basic report (& SQL) parameter. However, the users now want the parameter selection to also cause the display of the appropriate department logo in the report header.    

In the past, Ive done something similar in the VBA world using MS Access. Im wondering how this could be accomplished in SSRS. Is there a parameter selected event that I could utilize to run code to set a header image control at runtime?
Just to complicate things slightly, the SSRS report is being called from Microsoft CRM.  I suspect that this fact may limit my solution design options.

Thanks in advance for any feedback and ideas offered.
Dmac51