It's not photoshopped. The Dad of the two girls in the picture wrote about it on his blog:
FEED A BABY LIKE A BOSS
January 6, 2014
My daughters recently graced the front page of Reddit and imgur with this hilarious photo of my six year old feeding her baby sister with her foot. Or as one redditor liked to call it: feeting the baby”.
The photo has been making the rounds on the old Internet. It was picked up by Buzzfeed, the Huffington Post, etc.
While we don’t condone, encourage or ever want to see another ‘feeting’ going down in our house, we think the photo is pretty damn funny. We applaud her multitasking skills.
She appears to be like her daddy, lazy with a side of ADD.