Cow and the Fly Optical Illusion

This is one of the better illusions that require you to stare. The clarity of the picture after you follow the instructions below is soo amazing.

The Color in the photo of Cow is not well balanced (the left side is bluish and the right has too much yellow).To restore the color balance stare at the fly in the second diagram for 30 seconds,then look at the cow again.
You will see that the lighter blue and yellow colours in cow image getting a bit darker.