Specifies the type of a GdkImage.
|The original X image type, which is quite slow since the image has to be transferred from the client to the server to display it.
|A faster image type, which uses shared memory to transfer the image data between client and server. However this will only be available if client and server are on the same machine and the shared memory extension is supported by the server.
|Specifies that Gdk::IMAGE_SHARED should be tried first, and if that fails then Gdk::IMAGE_NORMAL will be used.