Looks like a good photo! Can you save it again in Hi-resolution? Make sure all your boxes are checked before hitting enter.

Without a High-Res, we really can't see the image properly, what we see here is a down sampled version of what you uploaded, this is why it's important to tick Also save full resolution image. You can still do this.
Go to;
My Stuff
my contest entries
find this entry and click on ;
edit entry
upload entry again and
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