A: San Jose, California, United States, B: Ann Arbor, Michigan, United States
In 1987, American software engineer 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, which he called Display, caught the attention of his brother John Knoll, an employee at Industrial Light & Magic, who urged Thomas to turn Display into a fully-fledged image editing program. Thomas took a six-month break from his studies in 1988 to collaborate with John on the program, after which Thomas renamed the program ImagePro. But since the name ImagePro was already taken, Thomas renamed the program Photoshop, and worked out a short-term deal with scanner manufacturer Barneyscan to distribute copies of the program with a slide scanner. Roughly 200 copies were shipped under that arrangement.
During this time, John Knoll gave a demonstration of the program to engineers at Apple in Cupertino, and to Russell Brown, art director at Adobe Systems in San Jose. In September 1988 Adobe decided to purchase the license to distribute. In February 1990 Adobe released Photoshop 1.0 for the Macintosh. Adobe photograph became the de facto industry standard in raster graphics editing.