Well, if you want something for editing photos that is truly free as in beer and speech, try the awesome darktable: https://www.darktable.org/
I'm also always blown away by how incredibly easy to use and at the same time how powerful hugin is. In this long list of for-pay stitching applications, Hugin is the only one of two which are free (again, beer and speech) https://en.wikipedia.org/wiki/Comparison_of_photo_stitching_...
