$64 million dollar question
Maybe you are looking at it from the wrong angle.
Instead of thinking of a cute image, look at it as a sales message. You can still have text in the image, it just can't be the main focus.
Proofreadings a tough sell, most people can read and write, and use a spell checker, and most people wouldn't consider the expense of asking someone else to do it for them.
In the same way most people can drive a car, but there are times when you really need a taxi
So maybe concentrate on the value of having your web content professionally checked. Maybe two images side by side showing a call to action, one of them with a typo. Then something cheesy like "Frank wondered why sales were down 37% since the new website went live..." Be proofread from only £xyx.
Here's one currently in my timeline. Not endorsing Fiverr, but it's a good example of how an image conveys a message, even with minimal or no text. A simple headline which you will scan read, and you know exactly what this is.
If you are in the market for a 'toon version of yourself, then maybe you'll click the link. Out of thousands of page impressions, only takes a few clicks to make it worthwhile.
Get the creative juices flowing