Its just the way she is standing, it makes her left knee appear lower than it is.

She's just short. And this image is taken from pretty close, so that little changes in distance to camera make a big difference in apparent length.

A typical smartphone camera's default "1x" zoom tends to be a pretty wide lens with a short focal length. So you stand up close to your subject when taking pictures or video.

And people's faces tend to look better when shot from at least eye level, especially with wide lenses from up close.

So if you imagine a 1.5 meter tall person photographed from 1.5 meters away, at height level, standing straight, the top 1/3 will take up about 18.435° of visual angle. The middle 1/3 will be 15.255°. And the bottom 1/3 will be 11.31°. So just like that, 0.5 meters can look 60% longer on the top portion of a subject than the exact same length, 0.5 meters, on the bottom of a subject.

As a result, there's a warped perspective where the things that are higher on a person's body or torso look longer, and things that are lower are further away and therefore smaller.

Bend the knees slightly and the difference becomes even more skewed.

We don't notice these things with our eyeballs because our visual cortex corrects for these things with a three dimensional model of the world around us, but still photos don't go through that same processing when perceived, so sometimes perspective plays tricks on perceived size/distance.

For a quick demonstration, pull out your phone and take a selfie from above your head, looking up at the camera. How small do your feet look, and does that match the real world appearance as you perceive them in real life?