It's OK, alot of people don't know that SMILE doesn't read it's enemy graphics from the ROM itself.
But, for future reference, don't link to a picture as proof, especially if that picture is only a picture of the sprite. It's kind of like me saying...
Look! Mario is in Super Metroid!
Here's a picture!
You posted a link to a picture that was hosted on the Chrono Compendium, only showed the Guard, and no Metroid ANYTHING in the background or foreground.
Actually, I think SMILE at one time or another, used the same Mario Sprite as one of it's enemy placeholder graphics. O_o