Can someone please tell me the object for "lock picture aspect ratio" for
pictures used in comments?

I want to programmatically prevent a photo from being distorted after I add
it to a comment box using the following code:
Selection.AddComment.Shape.Fill.UserPicture (Selection.Value)

I have found Selection.Comment.Shape.LockAspectRatio. But that only locks
the aspect ratio of the comment box itself, not the photo.

This is done conventionally in Excel in the following manner:
[Right-click comment border] Format Comment€¦ Colors and Lines [tab]
Fill: Color: Fill Effects€¦ Lock picture aspect ratio.

Thanks for your help.