After integrating MOSS 2007 and SiteMinder SharePoint agent it has been reported that images would not show up on the SiteMinder protected MOSS 2007 sites (certain templates or from the document library itself)
This is caused by the lack of an ability to allow anything to be unprotected by MOSS 2007. MOSS 2007 requires the user identity information even for the resources like the images from certain locations. For that reason removing the file extensions for these types of resources from the IgnoreExt parameter of the Agent Configuration Object, would enable the SharePoint agent to treat these resources like any other protected resource and thus would be able to provide the required user identity to MOSS 2007.
This is necessary due to MOSS 2007 limitations.
Note: Due to caching on devices such load balancers, this problem almost always appears intermittently.
Note: This is with the Agent for Sharepoint 2007