In photography and videography, I find that a green screen is an essential backdrop to have on hand. It is right up there with the standard white, gray, and black backdrops. So, knowing how to make your own green screen can really come in handy.
Film & Media
I have been an avid user of Photoshop for years. I actually started way back in 2001 using photo editing software. Back then I used Jasc Paintshop. But within a few years, I had switched to Photoshop. I am glad that I knew my way around it once I started blogging. It is probably the number one tool in my arsenal of blogging weapons, and with that tool, the most convenient editing skill is knowing how to create Photoshop presets.