GIMP vs Photoshop
GIMP and Photoshop are both programs that are meant to open and edit images. The major difference between these two is that Photoshop is proprietary and would cost a lot of money to purchase while GIMP is open source software and is therefore free for anyone to download and use.
GIMP originally stands for General Image Manipulation Program and started as a project for a couple of students in college. It started to gain in popularity after it was added to the GNU list and a community formed around it that improves and troubleshoot problems. At this point the name was also changed from General to GNU but the acronym remained unchanged.
Despite the eager community supporting GIMP, it is still not as advanced as Photoshop. Even if GIMP is equipped with a lot of professional tools, there are features that are essential to professional level editing absent in GIMP like non-destructive editing. Most professional photographers and graphic artists use Photoshop due to the ease of use and its very powerful tools. Not even the high price of the Adobe Suite of imaging programs deterred people who needed professional quality images from using Photoshop.
The problem with Photoshop is that it only supports two operating systems, Windows and Mac OS. Professional photographers are restricted to these two unless they want substandard images. Being a part of the GNU, the source code of GIMP is easily acquirable and compiled for multiple operating systems. There is a version of GIMP for every operating system available, making it a good choice when you cannot change your operating system to the two that Photoshop supports.
GIMP is best for photography hobbyists who just want to improve the quality of their photos without spending any money on the software. It is also suitable for amateurs who may want to learn the basics and the concepts of how to manipulate the images before turning pro and acquiring the associated tools.
Summary:
1. Photoshop is proprietary while GIMP is open source
2. Professional photographers prefer Photoshop over GIMP
3. GIMP is best for hobbyists or amateurs as a free alternative to Photoshop or as a learning tool before buying the expensive Adobe Imaging Suite
4. The Photoshop user interface is made up of a single window that contains child windows while the GIMP UI is composed of multiple windows
5. Photoshop is only available on Mac and Windows while GIMP versions are available for Mac, Windows, Linux, and UNIX