The darkness is easy enough to fix: Just turn down the opacity a bit. I agree with - Max -: at the size you're going to be showing these, the simpler...
It just means that if you use one of those textures, you cannot distribute the resulting map under a Creative Commons (CC) license. You can still do...
I am a visual effects artist at Zoic Studios in Culver City, CA. I am also the visual effects supervisor for the independent feature film Canyon Road (2012), the web administrator for the Christian Gamers' Guild and public relations officer for Fans for Christ.