CS3/CS4 - Calculate visible part of image

Hi,

To reduce image sizes i'm going to physically crop images. To do so I need to calculate a bounding box for the visible part of an image in a frame. How is this most easily done? I have tried the IGeometry on the kSplineItemBoss and the IGeometry on the child of the Boss, but none of these seem to yield information about e.g., location of the image inside the frame.

I hope somebody can point me in the right direction

Kind regards Toke