Another way that works for me is to open the render view (WINDOW - RENDERING EDITORS - RENDER VIEW).
Now in the RENDER menu - select RENDER - PERSP (to render the perspective view)
The resulting image will be a 600x480 software rendered scene. If you are using the mentalray template I posted ( http://dhost.info/tiddles/mentalray.zip
), then you can change the rendering type from Maya Software to mental ray.
Note: depending on your PC & and the complexity of your scene, the mental ray image can take a while to generate. I have had single mentalray frames that took over 10 mins & thats with a 3.2gig P4 with 1.5gig ram.
Now, to save this for web posting go to FILE - SAVE IMAGE and select JPEG as the file type. You should now have a .jpg under 100KB which is ideal for this forum.
Hope this helps...