Image analysis

I invite experts to provide links to programs for image analysis, so that we can contribute as a virtual community, in the study of some images of everything that is circulating on the network. There is so much material that certainly the UFO groups are collapsed. Let's see what we can do collectively, as well as we train in this important aspect of research.

I'm going to start with the simplest, which would be a minimal software for UFO photo analysis.
To make an initial study I recommend this site, which I have used in the analysis of my two photos taken in summer, in southern Chile:

Photo editor
pixlr.com