Open the PDF document. Click once on a picture. It should turn a shade of blue. On the top menu go Edit/Copy. Open a graphics editing program such as Photoshop or else open a Word document. Go Edit/Paste. The photograph should appear in your page and you can save it as a separate document.
If you have Windows 7, there's a "Snipping Tool" that I find very quick and easy for all sorts of purposes. A bit like the old Print Screen button, but croppable and with a few other options that don't require the use of Paint or any other editing program.