what is a good gfx program that is simple

[davidpsy]

what is a good gfx program that is simple like paint witch you can change the size or the img realy easy but also have paint brushes with differend shades of the color and you can switch back to just one color or use the paint brush also with a shadeing efects but easy not like a program that make adds on a pice of paper this program has to just be for gfx like paint i love paint i think its the easyest program to use to make gfx but i need shadeing efects and stuff if you can help me please tell me of such a program