why net to flatten img0?

[crystalbai]

Hello, I tried to use a different network with different inputs, I find out that in the minimize function the author using img0.flatten(), why is that? Thanks, because I also need to input image size information into my network.
I would really appreciate if someone could give me a hint!

[deepbluesea]

Return a copy of the array collapsed into one dimension.
https://docs.scipy.org/doc/numpy/reference/generated/numpy.ndarray.flatten.html