This is a limitation of the min and max number of rows and columns. If you open the Reporter window or look at the logs for the service provider, you will see the following:"Error: The application has to be unrestricted to override maximum columns and rows of the service.Error: The number of cols '19906' exceeds the maximum number of cols '15000' supported by the service."For more information:http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?TopicName=Printing_layouts_containing_an_image_service_from_ArcGIS_Image_Server