The photos you just posted look far better than your original post on here. As I said before thats a great looking pastel you have there, I just felt the colors were too off in the first photo and according to PS they were. I could have intensified the yellows in the photo I edited but I basically just corrected the white balance in PS not mush else. I wasn't trying to imply that you were trying to make something you dont have, I was implying that the way you edited(Auto WB in GIMP) made the photo look overly saturated and tinted. Sorry about making the snake look so old but I didn't try too.
Thats a great looking pastel you have there and I wouldn't hesitate for a second about taking it off your hands.