Is this shoe pink or gray?

A few days ago, I sent this photo to about 25 friends, along with these words I found on Facebook.

What color do you see?  Apparently, if the right-half of your brain is dominant, you will see a combination of pink and white, and if your left half is dominant, you will see it in gray and green color.

Minutes later, I sent myself a note, so I could share it with everyone who replied.

I saw a pink shoe with white laces and trim on Facebook. When I copied and pasted it into an email, I saw a gray shoe with green laces and trim.  When I went back to Facebook, it was green laces on gray.  But looking back to the email, it was pink again with white laces.  Then both were pink and white.  I sent the email, opened the one that came to me, and saw pink and white.  That's still what I see below as I re-send this note to myself.  Strange!  Or am I the strange one?  Why am I seeing BOTH pairs of colors?  I have no idea.  I even tried looking at it with one eye and then the other, but they were the same, usually pink with white laces.

Since then, I have even managed to see a pink shoe with green laces.  How?  I let my eyes blur until the colors started to change and noticed the white laces first turned green before the pink started fading to gray.