Depending on the situation, sure. If the comic doesn’t have a signature in the margins already (like XKCD) then credit in the title/body. If the signature is in the margins, and cropped out, then that’s bad form. Comics are often re-shared and the title/body doesn’t always come along.
After you remove the signature from the comics, credit is going to quickly get lost as the re-posts happen.
Depending on the situation, sure. If the comic doesn’t have a signature in the margins already (like XKCD) then credit in the title/body. If the signature is in the margins, and cropped out, then that’s bad form. Comics are often re-shared and the title/body doesn’t always come along.
After you remove the signature from the comics, credit is going to quickly get lost as the re-posts happen.