Correction. :-)
* M31, Orion and the Pleiades pictures come from Herm Perez :
http://home.att.net/~hermperez/default.htm
Just found this on the web page:
"Feel free to use these images, if you use them in a commercial setting please
attribute the source."
That's the license. :-) If you get clarification that "use" includes
modification and redistribution, then all is well and these can go in 'main'.