ImageJ is described as 'Public domain, Java-based image processing program developed at the National Institutes of Health. ImageJ was designed with an open architecture that provides extensibility via Java plugins and recordable macros' and is a Image Editor in the photos & graphics category. There are more than 25 alternatives to ImageJ for a variety of platforms, including Windows, Mac, Linux, Web-based and Android apps. The best ImageJ alternative is Fiji, which is both free and Open Source. Other great apps like ImageJ are MIPAR, Icy Image Processing, MountainsMap and OLYMPUS Stream.