How Referencing Images Works
When you make an image of a root application that references included applications from the database (that is, by not specifying an image file name in the references), all of those included applications are also imaged and added to the resulting image file of the root application. This may not be desirable, especially if you plan to have several applications share a common utility image.
If the included application reference contains an explicit image file name, the referenced application is not added to the root application image file. Instead, the root application will dynamically bind to the specified image file name at runtime.
During development, it is convenient (for debugging, and for keeping up with the latest versions) to reference included applications directly from the database. Therefore, you generally do not want to specify an image file name with your included application references in the Included Applications window. But, for deployment, it is more space-efficient to reference shared image files, rather than having the shared images be duplicated within the image file of each root application that uses them.