Harlan Ellison's discussion forum sometimes yields fascinating insights into SF history, such as his first professional sale. A forum user mentioned that he'd seen a copy of the July 1952 issue of Imagination for sale and that it contained a cartoon reportedly by Harlan.
Ellison confirmed this publication and stated the following:
You've stumbled upon my very first actual professional sale. I was in high school, East High in Cleveland, and one of my few friends was the brilliantly talented cartoonist for the East High newspaper, Ray Gibson. We both read sciecne (sic) fiction, and I thought up the cartoon and punchline, Ray did the art excellently, we sent it off to IMAGINATION and they paid us $25.00 This item looms large in my career, even if the bibliography omits it. It was the every start, save for the two serials in The Cleveland News. It is no. 1 in my Archive.
Ray is still alive. In Cleveland, I presume.
The cartoon, with the caption "My plates are killing me," is linked to above. The ISFDB entry for Ellison indicates this is one of only two interior art cartoons Ellison helped create during his five decade plus career.