Adobe Photoshop is the industry standard in raster graphics editing, such that the word "Photoshop" has become a verb as in "to Photoshop an image," "photoshopping," and "Photoshop contest," etc. It can edit and compose raster images in multiple layers and supports masks, alpha compositing and several color models including RGB, CMYK, Lab color space, spot color and duo-tone. Photoshop has vast support for graphic file formats but also uses its own PSD and PSB file formats which support all the aforementioned features. In addition to raster graphics, it has limited abilities to edit or render text, vector graphics (especially through clipping path), 3D graphics and video.
Learn how to use Photoshop or just specific elements of it using our Photoshop tutorials.