Typically, I found the answer empirically, five minutes after posting:
If an image is selected you get either a pointer to a Picture or
Pictures object, depending on whether one or more images is selected.
So, with

CComQIPtr<Excel::Picture pic = pAppXL-Selection;

pic is none null if a single image is selected.

Steve H

On 24 Jan, 15:16, wrote:
Hi

I'm trying to determine which shapes (images in my case) are selected
in Excel (Office 2007). However, attempting to get anything useful
from the IDispatch returned from application-selection fails e.g.

CComQIPtr<Excel::ShapeRange ShpRng = pAppXL-Selection;

results in SHpRange being NULL.

Has anyone actually succeeded in using the application Selection
property in Excel from a COM addin, or is this a big bug in Excel?

Incidentally, trying the window Selection property returns the same
IDispatch, again with no useful interface.

Thanks

Steve H