Adobe Photoshop is a raster-based image editing application that is used widely in design and art. Adobe Photoshop is able to open, modify and save image file and supports a large number of complex image operations.

Abobe Photoshop is available for Windows and Mac OS X. 

For some use cases and user groups, The GIMP might be an open source alternative to Adobe Photoshop.

Information about Adobe Photoshop

• Abobe Photoshop Homepage