Oh, why thank you! How very kind!  I love how helpful and nice people around here are. 

 I just played round a bit and noticed that taking or merging a few colors didn't affect the overall look of the piece, and while there is no rule for ammount of colors or dithering, it was good practice to find out what I could take away and still keep the overall feel of the piece.

 Nice job on reducing the colors, I can barely tell you took out any 

i didn't think there were too many colours, or too much dithering. There's no rule that says you need the fewest colours possible, and there is nothing wrong with dithering.   

Thanks for the pointers! I'm always open to advice. I'll try narrowing down the palette, maybe that will solve my compulsive dithering.

This has a loooot more colors and dither than it needs to have. Look at Christoballs profile, he does portraits of this size very well.