Extract jpg or png images from a PDF

There are a lot of tools available online to extract images from a PDF, but most of them are shareware or trialware. If you need just a single image, you can right click it in Adobe acrobat reader and copy paste it into Microsofts paint, Paint.net or (overkill) Adobe Photoshop. But if you have a PDF with several pages and several images on each page, you’d like to have it automated. That’s when you start your search for a good free/low cost utility. Or, you can write your own! Much more fun guaranteed!