If the camera had a fisheye lens, it would distort the parts of the craft that are in its field of view, but those appear without fisheye distortion.

Unless I'm missing something else, the curvature you see is likely due to the spherical nature of planets.

They just switched cameras, and this one doesn't show parts of the craft, so my comment above won't make much sense, but the curvature I see with this camera is similar to the one I saw with the other camera which shows parts of the craft.

The cameras aren't anything special. Take a look:

https://www.nasa.gov/mission_pages/station/research/experime...

One of them is literally a handycam-type consumer camera. You can read more about the payload here:

https://www.nasa.gov/mission_pages/station/research/experime...

Thats an amazingly large box considering weight and volume is expensive to get into space...

Because it captures more stuff at once? Why would you think anyone would need to deceive about the curvature of earth, that seems pretty well established?