My suggestion for improvement would be if you could have the parameter of parameter type Image as an instance parameter.
The reason for that is that we are not able to get the images right in schedules for Pipe and Duct fittings.
In Pipe and Duct types it is common that you use instance based families.
When modeling the Pipe and Duct runs we get several Pipe fittings in the schedules and most of the time we sort them by Typename, Size and Angle.
It would be great if you could embed images in the Pipe and Duct families and assign them to Instance Image parameters and use formula's to set the right image based on the angle of the fitting.