Is there any property that allow things like the following pseudo code(used in automation)?
objShape.PictureFormat.TransparentBackground = Microsoft.Office.Core.MsoTriState.msoTrue;
objShape.PictureFormat.TransparencyColor = some RGB color ;
You can use PictureFrame.TransparentColor property.
Also (if you use .Net version) you can simply add PNG image with some transparent
color inside and it should be shown with transparency.