Image Processing Software
There are many software packages available for remote sensing image processing. Some are free, some are quite expensive. Some are designed for a wide range of image processing tasks, while others are more specialize, and still others are primarily GIS packages with image analysis capabilities (in some cases quite extensive). The following lists are not exhaustive, and a listing here is not a recommendation by MontanaView or any of its members.
ArcGIS Explorer http://www.esri.com/software/arcgis/explorer
GRASS GIS https://grass.osgeo.org/download/
R (statistical software, but used increasingly for image processing) https://www.r-project.org/
TNTmip Free http://www.microimages.com/products/tntmipsfree/
PCI Geomatics http://www.pcigeomatics.com/