It’s been nearly 25 years since Adobe released the first full version of Photoshop, a program that would eventually become the go-to graphical editing tool for professionals and amateurs alike. In the event that you weren’t around back then to enjoy Photoshop 1.0, you can now download a free and legal copy as of today courtesy of the Computer History Museum.

The Museum said they obtained permission from Adobe Systems to release source code from the 1990 version of Photoshop 1.0.1 free of charge for non-commercial use. In total, there are 179 files in the zipped folder which contains about 128,000 lines of mostly undocumented but well-structured code.

Roughly 75 percent of the code is written is Pascal, 15 percent was done in 68000 assembler language while the rest if a mix of various other languages. Everything is included with the exception of the MacApp applications library that was licensed from Apple.

PetaPixel highlights the fact that almost all of the code was written by Thomas Knoll since he was the only engineer on board when version 1.0 was released. Thomas and his brother John originally wrote the software, known at the time as Display, for their own personal use. It was licensed to Adobe in 1989 and released to the public a year later. For the follow-up release, a second programmer was added to the mix.

Those interested in checking out the retro software can download it free of charge by clicking here. There’s a user guide and a tutorial available should you need it.