Hiya,
I have poser 6,
When I import a background its a bit hit and miss,
I think I have it set up ok, it fitts the screen, but then when it render the image is squashed with a grey border, but the figure is just fine.
This has happeded on the blood and gold background as well has a few others.
I really dont know what I'm doing wrong so any tips,hints would be very welcome!

For most situations I recommend not importing the background at all - or if you need it for reference, don't include it in the render. Instead, render over black and export your render as a PNG which you can easily composite over your background in Photoshop or whatever your image mangler of choice is.

Agreed.  Unless the background serves a larger purpose render without it, export as png and compose your scene in Photoshop or PSP.  But to answer the question, it sounds to me that your dimension settings are off.  Check to see if the 'match the preview window' button is selected.

I just use File|Import|Background. (I don't have Photoshop...;) Match lighting color, intensity, and angle, and it works.

I've been told that a better way is to use one of the props (the one-sided rectangle?) and use a background pic for a texture. Haven't played much with that, but I've heard it can accept cast shadows, etc.

Attached Link: http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2749857

The bottom line is: if you want to render a background image to your scene, there are several good reasons why it's better to apply it to a prop in your scene than to use the Poser Background.

The prop/background approach is an excellent one.  I forget but there is a posing tutorial which outlines step-by-step the method to accomplish this.  Of course keep in mintd shadows cast on a flat prop will yield flat shadows.  I used this technique to creat the background on my avatar.

If you don't want shadows cast on a background prop, apply the texture to the ambient node instead of to the diffuse. This will make it independent of lighting - best for landscape type backgrounds. 

Make sure your preview screen ratio is the same as your final render ratio, eg. 4x3 or 16x10.
Make sure your background image is the correct aspect ratio as your final render and about the same dimensions., eg. if you are rendering at 1024x768, your background should be the same size.
Make sure that in Manual Render settings your max texture size is at least the size of your background.
Best of luck.

Wow!
Thanks guys, :)