The trick to switching them in your head requires that you recognize one thing:
Your brain focuses on the patterns between her spinning and going up and down. Once you start with one of the two patterns you could recognize, your brain assumes this is the default (thus the difficulty seeing the opposite pattern). The way to see both is to alternate your perception thus: When the images foot sets down close to its shadow imagine what you already think it is doing (my default is clockwise, which means her leg is seemingly moving from the back to wrap around clockwise, kicking forward; from back to front.).

To invert that perception takes a moment, but switch the pattern your brain has assumed correct so that in my case I have to see her leg moving from FRONT to BACK. Remember this picture takes away the shading that humans use to associate the back from the front...which is the entirety of this mind trick.

So just remember, if you automatically see her leg swinging from the middle back to the middle front when her foot hits the ground, choose to imagine her foot swinging from the front to the back instead.

Lol....or you could just look at her nipples since they seem to be one of the primary focal points anyway :D

Oh and P.S. -- None of us are really "left" or "right" side dominant because we use all of our brains parts equally when going throughout everyday life. Instead of thinking of the brain as just two sides try to think of it like an orchestra where every part of the brain must play its own part at various times and in response to specific cues. Everything you perceive is actually like a multi-sensual "Symphony" that uses specific regions the brain (section of the orchestra) that all come together to create each individual experience.
Hope this clears things up a bit :)