Ultra Image Printer is described as 'Print any documents to images'. There are four alternatives to Ultra Image Printer for Windows and Mac. The best alternative is Image Printer. It's not free, so if you're looking for a free alternative, you could try Spool Pilot. Other great apps like Ultra Image Printer are Zan Image Printer (Paid) and PrintOnImage (Paid).
Spool Pilot makes it possible to convert printouts from arbitrary applications in several popular graphic formats as easily as it is now to save them in a PDF file. From the point of view of the user, the procedure of saving printouts is very much the same.