GIMP is an open source and free-ware program for photo editing and image manipulation which can be used for viewing, editing and enhancing your pictures. This software is loaded with basic to complex image manipulation features which makes it a great program for beginners as well as professionals. Although it has intuitive user interface but it may take you some time to get fully accustomed to this program as it is bundled with features.
User can open unlimited number of images at one time with its tile based memory management. With more than 150 standard filters and effects, GIMP can enhance your pictures like a professional image editor. GIMP is expandable with more than 100 extensions already available in plug-in browser and user can also customize this program according to the requirement. It has advanced capabilities like Perl, Python etc. and it can automate its operations with scripting languages.