Images can be added using indirect mode or pass-through
You can find details of these modes in the Image Handling section of
When you add an Image using the Doc.AddImageObject
method it will generally be added using indirect mode.
However some file types do not support indirect mode and can
only be added using pass-through mode. If this is the case the
operation of the Doc.AddImageObject method becomes identical to the
The value of this property tells you if the image will be added
using indirect mode. It is true for all image types with the
exception of EPS and PS.