Please someone tell me how are these pictures mugen-related?

mugen colorings I believe.

I think this is a derivative_work, but I can't remember anything specific about the reference_photo...

She is Nirvana(ニルヴァーナ), an arranged version of Alice Margatroid created by Lates. See also Lunatic's blog and these sample videos: (NicoNico and Youtube)

She doesn't really look much different from alice to me. Rather lame edit unless her clothes are the changing factor. These color swaps are as bad as Meimu personally. Sorry.

shades of titty monster..

Dalveska said:
She doesn't really look much different from alice to me. Rather lame edit unless her clothes are the changing factor. These color swaps are as bad as Meimu personally. Sorry.

After seeing this and this this, I can only think that these original M.U.G.E.N. characters all suffer from Middle-school 2nd Year Syndrome (Evil Eye variant)