To show the image directly, you have to use the IMG tags. When you're writing a new post, you can see an IMG button (to the right of the emoticons, under the
B). If you click the IMG button, all you have to do is put the URL for your image there (URL = the link to it).
Now then, the picture...
The eyes aren't lined up right. You drew them as if his head was straight, but it isn't. If his raised arm was down by his side, it looks like it would reach down to his knees, which is too low; they should only reach to around the half point of the thighs. The muscles on his other arm don't really make sense. You should draw a vertical line on the pecks to show their shape more if he's supposed to be that muscular. The leg to our right is too short; given the angle, it should appear to be longer than the other leg, unlike how it currently is. His hand on the right looks kinda gibbled...
The next main problem is the angle. His raised hand should be parallel with his body (facing it, not turned away from it); it would be pretty awkward as is. His abs are centered on his body, but they shouldn't look that way with this angle; they should be shifted over more to the left. Think of his body as if it was a 3D rectangle; the abs should be on the flat surface on front.

To add to how the body in your drawing looks too 2D, the belt doesn't look like it's wrapping around his body. If you think of it in 3D blocks again, you might be able to get an idea of how it should show on the side as it wraps around to the back.
The neck, head shape, hair, necklace, and details on the face look good (though the eye placement is off like I mentioned). The pants also look pretty good, but his crotch area looks totally flat. You don't have to make it bulge there or whatever, but maybe just add a small horizontal line where his two pant legs meet (draw a short line from that point towards the left). The colouring is pretty nice and clean, but the shading could be better. Also, he doesn't seem to have any eyebrows; I dunno if that was intended or not.