Great shot, the photo you see here has been down sampled, for quicker display, but it does not show it at the best quality.
Which is why we also have the option of also uploading a higher resolution copy.

Go to;
My Stuff
my contest entries
find this entry and click on ;
edit entry
Upload the image again
remember to tick;
Also save full resolution image.
Your image doesn't need to be enormous, anything between 2.5mg and 3.5mg is plenty big enough.
Good luck

The high res looks really good, Nice DOF