If you need many screen captures, this tool makes it easy to grab them, but you may run into a barrier with the trial period. It's 30 days (which is adequate) or three sessions (which is brief), whichever comes first. We had a few other quibbles that left us unwilling to part from the reliable, old, built-in PrintScreen.
Screenshot Master installs a small icon in your system tray. Using this tool is very easy, because you just click the icon to make it work or to access its setup menu. The menu launches a well-designed configuration dialog box that is simple to use. Screenshot Master worked well for us, and we liked the capability to select the file format (JPG, GIF, BMP), color format (full color to grayscale), and resolution (for JPGs). But we also encountered a few aggravations. First, but minor, was that Screenshot Master saved shots to its own program folder by default and offered no options for the user to change this setting. Second, clicking the system tray icon didn't simply capture the screen; it opened a little menu from which we had to select the screen-capture command. Third, when we opened the configuration menu and then closed the dialog box, closing the box also exited the utility, which used up one of our precious three trial sessions. Last, but definitely not least, all captures were full-screen, with no way to choose to capture just the active window.
In most cases, a good image editor includes a screen-capture tool. To pay for just this feature, we'd expect more from it. Our issues with this tool and its too-brief trial leave us more than satisfied with our system's built-in PrintScreen feature, which lacks some Save As options, but costs nothing.