I know the picture you are talking about, when UMK3 for Genesis & SNES and MKT for PS1 & N64 was coming out, there is an ad in my old Electronic Game Monthly magazine(I still have it) for MKT and it showed some character selection pictures of the characters that was going to be in the game and that picture of Human Smoke you mentioned is one of those pictures that was used in that ad, I hope that helps.

There is a site under www.trmk.org Go to that site, and choose the Ultimate Mortal Kombat 3 section, and choose arcade. It gives you the moves lists, and in there are bio pics of all the fighters. Human Smoke's is in there as the one you speak of.