This image was reported to cause someone's "very vivid and disturbing nightmares" when viewed, and victims who allegedly saw the image described the hand on the image as "beckoning.
Attaching the file — that is, spreading the word, is the only way to save oneself from the smile.
I do not move and do not speak.
Josh, I saw that smile dog you showed me.
Why did it have to end this way for him? Full story: creepypasta.