According to the example on the page, it's the cast singing the theme song or something. In other words, it's an auditory gag, so it doesn't work anyway for an image.
If the Monty Python And The Holy Grail credits are too hard to read, South Park would be pretty good.
The uppermost picture is completely illegible, but either of the lower two would do.
I see the Awesomeness.
Like the yellowish one more. The first one is illegible, and the third looks too much like a one man show.
Fight smart, not fair.
Yeah, second's my favorite, too.
And if I claim to be a wise man, well, it surely means that I don't know.
Existence Weighed Against Nonbeing
I like the 2nd one.
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A pocketful of saudade.
It's all text, might as well be a page quote.
Joke aside, I also support the second one.
The words above are to be read as if they are narrated by Morgan Freeman.
Uniocular
Well, I suppose if we can find an image that demonstrates it without being majorly text, that would be ideal, but as it stands, I like the Holy Grail one better, as it's a classic, and demonstrates the gag more effectively. The South Park one could just be seen as a one man show.
"It's so hard to be humble, knowing how great I am."
A pocketful of saudade.
Personally I don't think it would. The gag is often done in text, so one without would be atypical and hence not representative.
The words above are to be read as if they are narrated by Morgan Freeman.
The yellow Monty Python(?) pic is nice, I vote for that.
Hi
I can read the B/W Monty Python pic fine...you people need glasses. 
That being said, I'm fine with the second one.
Dragon Writer
I can read it fine, but I'm nearsighted so I can read fine details anyway.
An Ear Worm is like a Rickroll: It is never going to give you up.
Existence Weighed Against Nonbeing
I can read the first one, but the 2nd one is funnier because "llama" is an Inherently Funny Word.
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Hi
The second Monty Python pic's got enough support, so it's up, potholed, and tagged. I moved the page quote to the caption since it's also from the movie; if someone wants to put up a new quote, go for it. Locking up.
Maybe I'm dense, but I'm not seeing the gag here. Granted, I also haven't seen the show in question.
I think a better image would be the credits from Monty Python And The Holy Grail
"It's so hard to be humble, knowing how great I am."