True perspective can be fairly time consuming to achieve. You'll find a
perspective based stencil under File / Shapes / General / Blocks With
Perspective. This only supports single point perspective, but it
demonstrates the way to go if you wanted to take a solution further.
It occurs to me that you might talking about an image, in which case you'd
need to do some external manipulation prior to importing it into Visio.
Hope that helps.
Best regards
John
John Goldsmith
www.visualSignals.typepad.co.uk
www.visualSignals.co.uk