Thank you very much! It just happened that i couldn't upload my stuff here on PixelJoint. I'm trying to improve and i've done quite a number of images since this one. You're not the only one, who pointed out those problems and i tried to fix them. I'll be glad to get your critique again!

It's a very good effort for a second piece!

I have some crits though.

I notice that there is a lot of banding in the piece, especially where the moonlight hits his back.

There are some colors that are very close together which serve little purpose. It would be better to either distribute them more evenly value-wise, or simply remove one of the colors all together. Example.

This is a bit more of a stylistic choice, but if you want to make the piece smoother I highly recommend trying anti-aliasing. It is covered in the article I linked along with banding.

As for the readability, I can clearly tell what the sage is doing and what the candle and books are and such, but some parts I cannot tell so well. The wooden area under the table especially. It is important to take a step back and ask yourself if what you are making is clear to the viewer before going in and adding details and shading.

Lastly, these aren't related to pixel technique at all but more of a PixelJoint specific thing. Unless you think it is absolutely necessary, don't pre-resize the piece. People like to be able to see what it looks like at 100% and there is already a handy zoom tool in pixeljoint.

For the preview, don't just scale the whole image down. It's a good idea to crop it down to a part of the piece so people can be intriged and want to click to see the rest.

All that being said, welcome to PixelJoint! I think you have great potential, and as I said before this is a very good start.