I need a title for my essay that is saying that works of words are better than pictures. I was thinking of "a picture is worth a thousand words", but that advocates pictures, not words.
I'm not sure whether it fully fits your essay, but the phrase
The book is always better (than the movie)1
referring to film adaptations versus the books they're based on, gets a fair amount of usage. There are t-shirts, memes, many blog posts, etc. To some extent, the first half has also become a stand-alone phrase, as in the article "10 reasons why books are always better than boys".
Of course this phrase contrasts books with the films that are based on those books. Since books are made up of many words in a particular sequence and films consist largely of many pictures in a particular sequence (and are even sometimes called moving pictures), I think the analogy is fairly clear and the phrase could work for you.
There is even some use of these two phrases in contrast with one another, in the form of the question "If a picture is worth a thousand words, why is the book always better than the movie?" It's been asked on Yahoo Answers, there is at least one meme out there, and it's apparently the slogan of a copywriting company, to link to a few examples.
1 The phrase the book was better is probably more common, but the more extreme version seems to suit your purposes better. However, if you wanted to hedge your bets, you could use The book is (almost) always better or you could use The book was better: with an appropriate sub-title.
As Ben Franklin said,
A word to the wise is sufficient.
This doesn't reverse the word/picture mechanism of the OP's idiom, but nothing really does. What it does is express the value of a terse, cogent expression in bringing about enlightenment.
Interesting discussion of the origins of the phrase, as well as some parallels, found in blog entry Benjamin Franklin: Talmudist.
By the way, the full rendering of Franklin's phrase is:
A word to the wise is enough, and many words won't fill a bushel.
It would be nice to know more about the essay but 'It is better to tell than to show' comes to mind off the top of my head.
1001 words is worth more than a picture.