My screen size is 1024 x 768 and render window is 850 x whatever......I get my scene all set upand want to render at 1024 x 768 or bigger....I go into render settings and render size to 1024 x 768 when it is finished it is not the same as the preview the top and bottom and sometimes the sides are cut off....How do I get it to render to the exact dims, like I said it cuts the top and bottom off and sometimes loose a characters head or feet.......thanks.

Go to Render>Render Dimensions

Then pick Render to exact resolution

Click the Match Document Window button, then input the dimensions you want in the boxes.

When you render if the dimensions you picked are larger than the view window, you won't see a complete picture in the render window, just use the mouse & you can move it around to see it all. When you save (File>Export>Image) however, the picture will be the full one.

done that, did that and it didn't do that....lol........did all of that many times and still get a chopped off image...

The image can be seen in part only IN POSER's window....  however, put it in your favotite image browser and voila!   the whole image.....    Now.. you can enlarge Poser;s view window....   It will be big as your image...  not a good thing to have and very difficult to work around such a large window......  In Poser, If you shrink your image, as is, you'll notice it will look kind of funny and compressed...  you might as well save it to your drive and open it with an image browser..

In the manual settings of the render settings, set max texture size to the size of the width of your background picture.

Set Display -> Production Frame so you can see what's being rendered.

My idea should work, try it and see.