Here is a timeline of ImageJ development over the past decade.
NIH Image. The precursor to ImageJ, NIH Image was originally written by Wayne Rasband in Pascal for the Macintosh.
ImageJ. ImageJ was originally developed in 1997 as a cross-platform version of NIH Image.
ImageJ grew organically over time as Wayne Rasband continued to add features according to user requests. Now there are many hundreds, probably thousands, of plugins written by members of a diverse community.
MBF ImageJ. Though ImageJ has many users from various disciplines within the scientific community, it is particularly popular among microscopists. Several years ago, Tony Collins of MacBiophotonics (then of WCIF) began publishing an ImageJ for Microscopy online manual for using ImageJ as an analysis tool for microscopy. Along with the manual, he released a version of ImageJ bundled with many of the plugins (by various authors) described in the manual.
ImageJA. In late 2005, the ImageJA project was started (see this thread on the mailing list).
Fiji. In mid-2008, Albert Cardona of the Institute of Neuroinformatics at ETH Zurich and Johannes Schindelin of the Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG) created an "ImageJ distribution" dubbed Fiji (“Fiji Is Just ImageJ—batteries included”). One way to explain Fiji is via analogy: if ImageJ were a Linux kernel, Fiji would be a GNU/Linux distribution. That is, Fiji is ImageJ plus a collection of bugfixes and carefully maintained plugins for performing many common scientific image processing tasks.
ImageJX. In early 2009, a discussion on the ImageJ list (see this thread) led Grant Harris to create a Google group called ImageJX for discussing architectural improvements to ImageJ.
Imagejdev.org. This project and website were launched in October 2009.
Much still to add: BioImageXD, Endrov, Micro-Manager, TrakEM2, VisBio and more.
