A PhD student at the University of Michigan by the name of Thomas Knoll began writing a program on his Macintosh Plus to show grayscale images on a monochrome display back in 1987. This program appropriately named 'Display,' attracted the interest of his brother, John Knoll, an Industrial Light & Magic employee, who recommended Thomas create it into a full-blown image editing program.
Taking a six month break from his studies in 1988, Thomas collaborated with his brother on the program, which had been renamed ImagePro. Later that same year, Thomas renamed his program Photoshop and negotiated a short-term deal with scanner manufacturer called Barneyscan to distribute copies of the program with a slide scanner; shipping a total of about 200 copies of Photoshop this way.
John, in the meantime, made his way to Silicon Valley and gave a demonstration of the program to engineers at Apple Computer Inc. and Russell Brown, art director at Adobe. Both presentations were successful, and Adobe decided to purchase the license to distribute in September 1988. While John worked on plug-ins in California, Thomas remained in Ann Arbor writing program code. Photoshop 1.0 was released in 1990 for Macintosh exclusively.