Bruce,
WebI is web based application so the syntax for the image MUST be different, try
- ="boimg://servername//rootshare$//Image Location//
- "http://<YourServerName>:<PortNumber>/
Other Blogs &/or KB to check:
http://service.sap.com/sap/support/notes/1490046
WEBI Report : Dynamic logo image change
Regards,
Ajay