Automated screenshooting for every single steps will more annoy you than help. It would take far longer time to run a Test Case with automated-screenshooting; as taking a screenshot requires a few seconds (say 5 seconds) each. If your Test Case has 40 steps, then running it would take 3 minutes longer. Also you would have to spend long hours to look up a single valuable image out of dozens of garbages. A PNG image file occupies so much disk space (e.g, 2 mega bytes) that you would have to swipe the garbages away manually.