Comment by nick_g

I don't use it too often, but it can be really helpful for getting a perfect crop of a specific element. With firefox's screenshot tool you can select the visible window, page or a specific element which has advantages over my os's tool. If I want a clean crop of an element with the os tool, I either have to open my rough shot in an image editor to get the crop right, or be very precise with my selection rectangle. I'll often use the os screenshot if I'm just sending a quick image to friends, but if I want it to look nice the browser tool is easier and faster