Are you using Nurbs planes or actual image planes?
If its the first I would create them on layers and make them non renderable and locked in postion.
If its the second you could create new cameras for the front and side, attach the image planes to these and lock them but not use them to view the planes (just use the std front side etc)
Not really put much thought into this as I use Nurbs planes ratehr than image planes (unless i'm rotoscoping of course) so thre ight be an easier way
"No pressure, no diamonds" Thomas Carlyle