You can drag and drop (or use Open) and load an image from within the 3D gamut area (same Open you'd use to access a profile). But it should be small or this app will bog down big time.
Thanks for the reply, but this does not work (or I am doing it wrong):
1) Open Grapher window, make sure it's active.
2) File, Open.
3) Open JPG or TIFF file.
Image opens in the Color Worksheet window but is not graphed.