Well... here's my two cents.
There is a difference, but it isn't the one you've said.
Comics, whether short or long, are comics.
Sequence of panels (whether visible or implied) are comics.
Cartoon is an aethetic . It is less representational (re: realistic).
In truth, any character can be rendered on a scale of not cartoony (realistic) to cartoony (superdeformed/chibi).
realistic batman vs. cartoony batman vs. chibi batman
These are all drawings, but none of them are comics.
Why?
No panels.
I really recommend you read Understanding Comics