Even if you've never worked with images on your computer, you may have heard of Photoshop. Available for both Windows and Mac, Adobe Photoshop is an extremely powerful application that's used by many professional photographers and designers. You can use Photoshop for almost any kind of image editing, such as touching up photos, creating high-quality graphics, and much, much more.
Photoshop is seen by the overwhelming majority as the de facto pinnacle of image editing and manipulation. Whilst revered for its vast tool set, seemingly unlimited plugins and general, all-round power, it is out of the price range of many average users looking to learn / dabble in a little Photoshopping. Each year, Adobe beefs up its umbrella of Creative Suite products (encompassing Photoshop), with prices remaining higher than most other paid software out there, but in something of a turn up for the books, Photoshop is now free.