Skinning help!

[reflected]

I would like to make some kick-ass skins, and I almost succeeded. almost...

I opened one of the default jpegs in psd, and started building up layers as usual. Then I flattened the image, saved it as a jpeg - not full quality but something like 1-011 so that it doesn't exceed 5-600 kb - but in game the quality of the texture wasn't very good. I could see brighter green patches n the green, etc....

What am I doing wrong? Thanks!