If you didn't make the art, don't upload it, no matter how much you want to, it's not yours and therefore shouldn't you upload it.
How would you feel if you actually drew a really good picture and someone came and stole it from you, claiming it as their own and refusing to delete it? It's not fun.
Stealing will not improve your artpiece.
If you don't like how you draw, then keep practicing, look up references on how to draw the parts you find difficult to draw.
Just please do not steal other people's artworks, because it will result in your account getting banned from deviantart.