Well, actually, the title is a tad misleading. I don't know who the very first person was to claim Luigi was in Super Mario 64 or who created the first doctored screenshot to support that claim.
However, I do know how they did it, whoever it was, and that is the subject of this ancillary entry.
I recently added my own material to the "Luigi in Mario 64" rumour (which is, for all intents and purposes, long dead) in the form of this picture...
It's as simple as they come, this picture. "Luigi" superimposed over a shot of Mario looking to his left.
I posted this on a Super Mario 64 Facebook fan page not too long ago, where it seems to be fairly popular. However, I get the idea that it's still fooling people (despite the word "simulation" written in the bottom right corner). So, to dispel any remaining hints of deception, I shall recount how I made this screenshot.
Using a Super Mario 64 ROM, I took a much earlier shot of a GameShark costume recolour code in action. This shot here...
This is my own Luigi code, the exact colour values in which I will not disclose. Now, the green colour of Mario's hat and shirt and the darker-than-average blue colour of his overalls are genuine. I set them using the costume recolouring codes. The "L" on his hat is not genuine -- I put that on, myself, using Microsoft Paint.
So, I took that picture. Then, I blanked out the void-space around Mario, ending up with this...
I used that wonky magenta colour because, as I intended to insert "Luigi" into other pictures, I needed a transparent colour that cannot be found on "Luigi", himself -- sort of like on the evening news. There's a weatherman standing in front of what appears to be a map, when in reality, he is standing in front of a matte-screen coloured with something that isn't commonly found in clothing and doesn't reflect its colour onto skin.
I, then, took another screenshot with the Mario 64 ROM: this one being a normal gameplay shot of Mario standing in a palace corridor, facing the camera. I waited to take the picture until he turned his head in the direction I wanted to put "Luigi", that way it would appear as though he were looking at his brother.
Now, simply superimposing that "Luigi" over the screenshot of Mario would be a bit hasty. Why? One glaring reason... Luigi would have no shadow. The solution is simpler than one may think. All I had to do was to copy Mario's shadow and feet in Microsoft Paint and paste them where I wanted Luigi to go. Since Luigi is, in fact, a recoloured Mario, his feet fit perfectly over the copy. Also, the carpet texture in the featured room is complex enough for one not to notice a slight square-shaped repetition around the shadow.
So, Mario and Luigi in a Super Mario 64 palace corridor...
1. Recolour Mario
2. Photograph Mario and blank out the void space around him
3. Photograph Mario without the recolour
4. Copy Mario's shadow and place it elsewhere in the picture
5. Superimpose the recoloured Mario over the shadow
6. Achieve Internet fame!
