:< newbie here.
in blender is it possible to put a uv map onto a mesh and use is as a displacement.
I have tried to use the dispaint script, it is not very accurate. I wanted to make a image in gimp and put it on a mesh plane and displace the image.
if anyone knows please help. 
Yes it is possible. Iām not familiar with the dispaint script as the last few versions of blender have had displacement mapping built in. Displacement mapping in blender does not create new geometry but only moves the existing verticies of your mesh (only visible in the rendered image). To get really good results you have to make sure your base mesh is fine enough (ie. a relatively high subsurf value) to show the detail of your displacement map.
2.36 now also has true normal maps which may be good enough for what you need see
http://www.blender3d.org/cms/Normal_Maps.491.0.html
Hope this helps,
GreyBeard