I'm not sure that's from them, though...
Let's look at the evidence. silly humor - post 'em here! [warning some NSFW and adult content]
1) This screenshot was captured within the first minute or two of it being posted.
2) The up arrow is orange, meaning that whoever took this screenshot upvoted the joke.
3) This joke has only one upvote.
4) The screenshot shows that the joke is positioned just below the OP even though the OP is 9 hours old.
Now, let's consider how Reddit works:
4) The reply text box is just below the OP, and when you make a comment to a post, it will show up (for you) above all other comments (until you refresh the page).
3) & 2) When you make a post or comment on Reddit, the site automatically makes you upvote yourself.
1) It's unlikely that the joke had existed on the site long enough for significant up- and down-voting by others.
Due to this evidence, I feel reasonably confident in saying that this "mikeseese" person who made the joke is also the person who took the screenshot.
And it just may be that those who are more familiar with Reddit on mobile could see other evidence that makes it even clearer. For example, I think it's possible (though I am not sure) that the "profile" icon next to mikeseese's username or the color of the username only shows up for the currently logged in user.