Remove Lena Image

[Piemontez]

I believe there is no longer a need to use this image (LENA), neither for convenience nor to be cool among men.

Note that IEEE itself is already banning the use of this image in its articles.
https://books.ieeeauthorcenter.ieee.org/prepare-your-book-manuscript/create-original-graphics/

[elliotberry]

Yeah, this is a github yikes lol