Google Not Pulling Featured Image

I’m trying to put a post on Google+ and it’s not pulling the featured image. I have the Yoast SEO plugin and ItempropWP plugins and it appears that the meta itemprop is set but it’s still pulling an image from my sidebar. The post in question is:
http://www.germanpearls.com/10-ways-to-improve-iphone-battery-life/
Anyone know what’s going on?
Thanks in advance!