"You wanna do a funny drawing? That's fine, but don't portray them... with them eyes and as if she doesn't know how to carry a child …" another fumed.
Another angry fan wrote: "I do not like this illustration of the Royal Sussex Family. A brilliant and elegant couple that depicts a cross eyed Prince, a loopy, distressed Princess and a hysterical crying Royal baby."
"This picture is trash," another raged, while someone else demanded they "delete this".
Many others called out the drawing as "nasty" and questioned the apparent lack of ethnic diversity given to the baby.
"I think the baby will have a bit more ethnic features than portrayed," one person said.
"She wants to raise the baby fluid gender......why is baby in blue??" another asked.
The illustration, drawn by French studio Fairepart, has come under fire after it was shared by a Meghan and Harry fan page on Instagram when news broke the pair had welcomed their yet-to-be-named son.
The post read: "Welcome to the crazy world, little guy. I've chosen for this moment a lovely and funny illustration by @fairepart_studiopostscriptum that at the end of the day, it's how is it when we got a baby.
"Funny, crazy and lovely! (and Prince Harry crosses eyes is clearly a lovely joke for the craziest moment of our lives, the moment we have our child in our arms!)."
The same studio also shared another drawing, showing the new family in a less animated manner.