The macro below may do what you want. It sets the wrapping style of the
selected shape to Tight and the Horizontal alignment to Right - both the
width and height of the shape are set to 3". The shape will be positioned
relative to the margin.

Note:
1. If the wrapping style of the selected shape is "In line with text" when
pasted, you must insert the following code line _before_ the line "Set oShape
=…":

Selection.InlineShapes(1).ConvertToShape

2. If you want to set only the width to 3" and scale the shape
proportionally, change “msoFalse” to “msoTrue” in the line : “
LockAspectRatio = msoFalse” (the “:Height =…” line is without importance
then).

The macro:

Sub ResizeAndPositionScreenDump()

   Dim oShape As Shape
   
   Set oShape = Selection.ShapeRange(1)
   With oShape
       ‘Change msoFalse to msoTrue to scale proportionally
       .LockAspectRatio = msoFalse
       .Width = InchesToPoints(3)
       .Height = InchesToPoints(3)
       .RelativeHorizontalPosition = wdRelativeHorizontalPositionColumn
       .Left = wdShapeRight
       .WrapFormat.Type = wdWrapTight
   End With

End Sub