JAR File (Upgrade or Unix)
To upgrade to v1.38 or install ImageJ on a Java-enabled machine, download ij138.zip (2MB) and extract the ImageJ directory. Includes Mac and Windows launchers. The Upgrade page has pre-release versions.
Mac OS X
Download ImageJ 1.38 (1.7MB) as a double-clickable Mac OS X application. (Instructions)
Linux x86
Download ImageJ 1.38 (35MB) for Linux x86. Includes the Sun Java 1.5.0_09 runtime and the ImageJ source code. (Instructions)
Windows
Download ImageJ 1.38 bundled with Java 1.6.0_02 (21MB) or without Java (1.7MB). (Instructions)
Mac OS 9
Download ImageJ 1.36 (2.1M) as a double-clickable Mac OS 9 application. (Instructions)
Documentation
Download the ImageJ documentation (10MB), in HTML format, as a compressed zip archive. The JavaDoc API documentation (567K) is also available.
Source Code
The ImageJ Java source consists of 77,000 lines of code in 242 files. It is available as a zip archive and as colorized and browsable HTML.
Example Images
31 downloadable sample images and stacks are available in ImageJ's File>Open Samples submenu. These images, and more, are also available as a 8.2MB zip archive.