I'm working for the first time with ArcMap's relatively new image analysis window, and am using the "image difference" function to calculate change between two images which I have performed a supervised classification on.

Each of the two images have only two types of land cover, forest and pasture; however, when I conduct the "image difference" analysis, I receive a raster with a ramp of 1 to -1. My question is how to interpret it? I.e. I'm looking to be able to symbolize where forest remains forest, forest changes to pasture, pasture remains pasture, and pasture changes to forest. I know this should be easy, and is so in ERDAS, but can't figure it out in ArcMap. Thanks in advance for any suggestions, David