Right, Andrew, it does work in the Designer. Perhaps, if you add an ImageView in the Designer you must add an image to it in the Designer, too.
If you want to assign an image to an ImageView in the code, you should not create the ImageView in the Designer, but in the code only, such as with
Dim ImageView1 As ImageView
Activity.AddView(ImageView1, 0, 0, 100dip, 100dip), and then,
ImageView1.Bitmap = (...)
So, I believe you can either work with the Designer or in the code. In a way, that would make sense.