Crop the picture down to just the pooch. Then resubmitted into the avatar again.
Yeah, it's a little tricky. You have to crop it down more on one side to get it to center. It usually takes me a couple times to get one right.As you can see below... this is the actual pic I use for my current avatar. Notice how I had to crop it and it's still not centered perfectly.
Looks great like it is... much better than mine. I'm 'bout due to change it anyways.