I'm lucky enough to have Adobe Acrobat Reader 6 and so can save documents as a jpeg etc. I'm not sure if Adobe Acrobat reader can do it - a free reader is available from the following link: http://www.adobe.com/products/acrobat/readstep 2.html
If you select "File" and scroll down you should see "Save as ..." and in the type of file dialogue box there should be an option to save the page as a jpeg.
If this option isn't available then there are some trial software packages that can do the job and some of them aren't all that expensive to buy. Give them a try first. Some links for you are below.
If all else fails, use an imge editor to take a screen grab of it. A completely unsophisticated way of doing this is to press the Print Screen button, then run MS Paint and press Ctrl + V
Or if you have Adobe Photoshop you can open the PDF and save it as an image file. I think that PS will only open one page of a PDF doc so you might end up with 4 images for a 4 page document