...it's absolutely someone else, I mean, we all have seen her feet (and their shape) and her ass and pussy before to be able to spot, that that's not her....
Besides, she never really uses a yoga mat.
Apart from that, nice pic, and I think it would pretty much look like that with Marlin
Unfortunately, the biggest giveaway that it's not Malin is that she'd never take a picture like that. Not even if she were wearing lingerie or a swimsuit.
I used google search and I found the original picture. It's from nakedbaker.tv. It's annoying when someone puts images into context but doesn't cite the source. The bottom part of the image, containing the name, was simply cut off.