I have photoshop, but I don't know how do do that...
It's editing the Hue/Saturation. In Photoshop Elements it's Enhance > Adjust Color > Adjust Hue/Saturation, but I don't remember how it is in actual Photoshop. It's been a while.
I just used the paintbrush, burn dodge, and color replacement tools. That's the only way I know how.
OMG! I love all the dragons you made! They are so COOL! I wish I knew how to do that. I'd probably take a picture of my sister and make her look like an alien, or a boy!