Jennifer de Guzman, E-i-C of SLG Publishing, has this to say in an entry in Blog@Newsarama's "I ♥ Comics" series:
Here’s a confession: Comics are not the storytelling medium I love best. That place in my heart belongs to prose. I have degrees in English literature and creative writing, and when I tell stories, prose is the medium that comes most naturally to me. I adore words, and even as a kid didn’t balk from reading books without pictures in them.
However, as much as I would like to believe that words can express everything, I know that sometimes they can’t, and that sometimes they need to step aside and let images do the talking.
Think of a funny story that you were a part of. Think of how many times you've told that story, grinning and trying to keep yourself from laughing, and you get to the part about how his pants were around his ankles and he was covered in pistachio pudding and that's when the fire department showed up...and then you look up and realize that you're surrounded by a sea of blank or quizzical looks. You know the feeling, right? What do you say at that moment? "Well, I guess you had to be there..." Some things, you just can't describe with words.
It is, of course, possible to write enormously funny prose. Possible, but difficult. The people who can write truly laugh-out-loud funny prose are few and far between, and generally don't get the credit they deserve. Neil Gaiman described part of his impetus for writing Anansi Boys as the desire to write something funny. It was generally assumed that the collaboration between himself and Terry Pratchett on Good Omens involved Gaiman plotting and Pratchett dancing around in the background tossing out jokes. Knowing that this was not the case and desiring to demonstrate his own ability to be funny, Gaiman set out to make Anansi Boys funny. And it is - but in a more dry, witty, PG Wodehouse kind of way, the way in which you read something, smile and say to yourself, "That's funny," not the way in which you actually laugh as you're reading. Gaiman is a terrifically talented writer, of course, but has a tough time making readers laugh. Even his friend and collaborator, the aforementioned Mr. Pratchett, widely acknowledged as one of the great living writers of humorous prose, can't do it all that often. Or try reading one of the rash of books released by stand-up comics about ten years ago - Jerry Seinfeld's Sein Language, or Tim Allen's Don't Stand Too Close to a Naked Man, for example. Again, amusing, but not really funny.
Switch mediums and you've got something else altogether. Get Jerry Seinfeld actually performing, and the material comes alive and is hilarious.
Which brings us to comics - the first strip pictured above is by the great MAD Magazine cartoonist Sergio Aragones. It gives us a quick and humorous little story with no words at all. Not only does it not need any words, the joke only works visually. Try taking the same gag and making it funny as a prose piece or a joke you tell your friends at the bar.
Better still is the "9 Chickweed Lane" strip below it. The Aragones piece could work as some form of motion picture just as well as a comic strip. The "9 Chickweed Lane" strip works only as a comic strip. The gag depends on the interplay of words and pictures, but moreover, it depends also on the familiarity of the viewers with the conventions of the comic strip. It can't be translated to another medium, and it presents a bit of humor that no other medium could create.
This, I suppose, is part of the reason why humor strips dominate the newspaper comics page while adventure serials and soap operas have disappeared either to the dustbin of comics history books or "They still publish that?" obscurity. Although humor is possible in all media, it is something to which comics are uniquely suited.
Take that same story, the one with the pistachio pudding and the fire department, and turn it into a comic. Instead of your audience hearing events second-hand, you've suddenly turned them into...well, yourself. A first-hand observer of the events. Maybe I'm wrong, but I'm of the opinion that you're going to get a lot more smiles, chuckles and outright belly laughs that way.
Might be there's something to that old saw about the value of a picture, after all...