Wow, that's really strange how it throws off your perception. There's nothing blurry about the pic, yet it almost comes across that way. Very cool find.
The effect is because the human eye actually has a very fine point of focus. If you were to look at a tight multicolored grid, you can test this out for yourself. Focus on a spot and then try to notice a spot simply 2-4 inches below.
For another kewl perception trick use google and search for "eyes suck at blue". Very interesting reading for knowledge types.