Hugin
Assemble a mosaic of photographs into a complete immersive panorama, stitch any series of overlapping pictures, more.
Hugin is a cross-platform imaging toolchain for stitching panoramas and straightening images on a computer. See Carl Bennett (@looeee) tutorial in the documents area on the Theta Facebook group. Hugin can be used to combine images taken at different exposures into one HDR photo, even when a tripod wasnt used during shooting. It can be used to combine multiple astrophotography images to reduce noise, when the world has turned and the stars have moved. By taking two pictures, and moving your body you can easily remove your big thumb from a photo. It can also be used to print out a picture that with scissors and glue can be made into a 360 ball.