Hi Wayne, check out Max's RasterImage script:
http://moi3d.com/forum/index.php?webtag=MOI&msg=7547.55

and also his Heightmap script which you can get from his file archive:
http://moi.maxsm.net/media/files/
and the discussion thread on that one is here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=7547.1

- Michael