PhotoShop.

A Little Bit about the Software:-

Adobe Photoshop, or simply Photoshop, is a graphics editing program developed and published by Adobe Systems. It is the current and primary market leader for commercial bitmap and image manipulation, and is the flagship product of Adobe Systems. It has been described as "an industry standard for graphics professionals"and was one of the early killer applications on the PC.
Early History

In 1987, Thomas Knoll, a PhD student at the University of Michigan, began writing a program on his Macintosh Plus to display grayscale images on a monochrome display. This program, called Display, caught the attention of his brother John Knoll, an Industrial Light & Magic employee, who recommended Thomas turn it into a full-fledged image editing program. Thomas took a six month break from his studies in 1988 to collaborate with his brother on the program, which had been renamed ImagePro.Later that year, Thomas renamed his program Photoshop and worked out a short-term deal with scanner manufacturer Barneyscan to distribute copies of the program with a slide scanner.

Features

Photoshop has strong ties with other Adobe software for media editing, animation, and authoring. Files in Photoshop's native format, .PSD, can be exported to and from Adobe I

ImageReady, Adobe Illustrator, Adobe Premiere Pro, After Effects, and Adobe Encore to make professional standard DVDs and provide non-linear editing and special effects services, such as backgrounds, textures, and so on, for television, film, and the Web. For example, Photoshop CS broadly supports making menus and buttons for DVDs. For .PSD files exported as a menu or button, it only needs to have layers, nested in layer sets with a cuing format, and Adobe Encore DVD reads them as buttons or menus. Photoshop is a pixel-based image editor, unlike Adobe Illustrator, which is a vector-based image editor.
Photoshop can utilize the color models RGB, lab, CMYK, grayscale, binary bitmap, and duotone. Photoshop has the ability to read and write raster and vector image formats such as .EPS, .PNG, .GIF, .JPEG, and Fireworks. It also has several native file formats:
The .PSD (Photoshop Document) format stores an image with support for most imaging options available in Photoshop. These include layers with masks, color spaces, ICC profiles, transparency, text, alpha channels and spot colors, clipping paths, and duotone settings. This is in contrast to many other file formats (e.g. .EPS or .GIF) that restrict content to provide streamlined, predictable functionality. Photoshop's popularity means that the .PSD format is widely used, and it is supported to some extent by most competing software.
The .PSB (Large Document Format) format is a newer version of .PSD designed for files over 2 gigabytes. The .PDD (PhotoDeluxe Document) format is a version of .PSD that only supports the features found in the discontinued PhotoDeluxe software.