How to cut a specific segment of an image in Unity using a script?

Question

Unity

Hello everyone, I've run into a problem and I can't quite figure it out. The bottom line is this:
The user takes a photo of himself, his photo is loaded into Unity. And then I want him, for example, to be able to trace the outline of his body and cut it out for further manipulations with it. How do I
present it? In general, the photo becomes a texture of a plane, and then I would like this plane to be not square, but take the form of a previously selected contour of a person. If you can come up with a better solution - write. Help please, thanks in advance)
PS
I know the code for calling the camera, taking a photo, I specifically need to solve the problem with cropping the image along a given contour.