What are the criteria for validating Tuxes?I submited a Tux G2 of mine and it was refused.Can i know Y?

It would be more helpful if you posted a link to the image.
 
Of course, only the validator can tell you why it was refused ... though the most common factors are:
 
- License violation: For example, many people just resubmit other persons' tux under their name.
- Aliasing: If the tux has rough edges.
- Other quality issues: Like Cut off shadow, bad coloring, etc.
 
Once again, post your tux here so we can better help you out.
 
PS: By the way, if you submit a normal, unoriginal tux that you made using a tutorial, it will not be accepted into the gallery. No "Jeans tux" or "Shorts tux" or "My first plain G2 tux". Be creative, make your own tux!

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i made this tux with GIMP.

idk how to make tuxs with accesories like the other tuxs in the gallery so i decided to make the eyes manualy using the pencil tool and the other parts with  bucket fill&rectangle tool.its totally mine.you can see if you zoom the square pixels mad with the pencil.

Like I said, there is heavy aliasing. You can see the edges and square pixels. The veins in the eyes are too ... pixelated. Make them smoother. Instead of the pencil tool, use the Brush tool with hardness at 0%. That makes the lines smoother.
 
And you've taken a 256x256px tux and enlarged it to 512x512px. That's why everything looks so blurred. Either create your own tux from scratch at the size, or keep it at 256x256px.
 
Lastly, I can see that you tried to use the lasso/magic wand tool to manually take the tux out of a white background. Don't do that. Simply take one which already has a transparent background in PNG format.
 
Also, I get the bloodshot eyes, but why are his arms, head, and stomach red?
 
And finally, whatever accessory you want to make can be made using the shape tools, blending options, gradients, and the pen tool. Like how about putting an arrow in his head with blood gushing out?

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Glomping the internet populace.

One forum at a time.

i have uploaded here a 256x256  but i have changed the resolution because i thought imageshack would make it smaller.the arms and sotmach are there to show how the tux is going to blow up