These are Schlitzie's scenes from the movie "Freaks".  I tried to get at least one shot of every scene he was in.  All photos are in the same sequence as in the movie.
(below)
Photo Detail; Clyde Beatty Circus, Combined Sideshows, author's collection.
If you're still not convinced, here are two close-up side by sides taken from  approximately the same angle.
The pic on the left is a photo detail taken from Cult Movies & Video magazine of Schlitzie taking a bow.  This pic was taken to use as promotional material for "Freaks".   As you can plainly see, Schlitzie's face is much rounder than his double.  Also, the double on the right has a much more normal-looking forehead. 
Is this the gentleman used in the final sequence in the film?

This pinhead has been identified as "Augustus". Was he a true pinhead?
Ring around the Rosy
Schlitzie finds comfort in the bosom of Mme. Tetrallini
Second Rollo (in honeyed tones): How are ya, Madame Tetrallini?
The bearded lady had her baby
"My, Schlitzie!  What a beautiful pink dress.  My, you look pretty."
Acting bashful.   Note Schlitzy's wrinkled scalp - a
characteristic associated with microcephaly
Utters unintelligibly
Why?  Perhaps Schlitzie was sick, or maybe he just hated being wet  Or perhaps this scene was re-shot and Schlitze was not available.  Then again, maybe Schlitzie's handlers were not comfortable giving him a knife (if it wasn't just a prop) to hold and crawl with under such circumstances.
A strange gesture, as if thumbing a ride but he probably meant to give a "thumbs up"
The freaks lie in wait for Cleo and Hercules
Acting jealous, telling off Phroso These two video captures clearly show that a body-double was used in the final revenge scenes
His receding forehead emphasizes the brow ridge
Schlitzie has picked up the mannerism of covering one's mouth when laughing Schlitzie's last scene in one of the circus wagons
A good look at Schlitzie's profile, his small skull, and pronounced overbite If you carefully observe this scene, Schlitzie, quite matter-of-factly, picks up a napkin and wipes his hands
A good view of Schlitzie's topknot.  She approaches the Snow twins to scare them away. Schlitzie's turn to drink from the loving cup
Pats Phroso's chest after gently striking him in "anger"
The wedding feast scenes.  Schlitzy guffaws because this is the sequence in which Cleo is laughing uproariously in a drunken stupor