Seperating beginners from the rest.

[Ultimecia]

I would suggest two simple rules/etiquette:

If you're the one posting a sprite: You posted to show off and ask suggestion to improve, so deal with the critique.
If you're the one reviewing/commenting a sprite: Remember to critique is different from bashing. Give constructive feedback or shut up. For example "She looks fat" is different than "She looks fat, maybe if you remove one pixel or two from the rip may help"