No, no generally not. I have asked for the next page of a comic though, to continue the story or links to ealier pages so I can start reading someone's comic, but not on a single narrative moment. Sometimes the one moment is enough to get a general idea so further story knowledge is 'unneeded', or it's just more fun to come up with one.
Agreeing with the people who point out having that single moment is part of what helps make the image impact you so. Knowing every little detail of every image and how it relates to this or that can detract from the mystery and wonder-inspiring feeling drawn from the image.
Personally I find that if I post a story and leave out a few details but never get a comment asking things such as what happened next, what caused it, what inspired me to write it, etc. I feel like there's little interest in what I wrote and that's very discouraging to me as a writer. So yes, if I'm intrigued by something enough I'll ask about the story behind it or what inspired it. I don't see it as a way of saying "This requires more, there's not enough to it." or "I don't feel your art is good enough." I see it as a way of saying "This is really good and I'd like to know more about not only the piece but about the artist."