And trying to decide what a notable or significant
artwork might be
seems to smack with the same problems that plagues Wikipedia in terms of
notability of people.
The Foundation already daily receives complaints about deletion of
articles about various artists,
works of art, web comics.
I can understand where Mindspillage et al are getting at (Guernica or
similar works are notable, others aren't)
but, as you rightly point out, this will be fraught with questions like
"why do you have a picture of <insert artist's work>
and not of <insert artist's work>"?
This will be especially acute since, at least I suspect, some comics are
much better known among the people who
read Wikipedia than some allegedly "important" modern artists.
And finally, I don't see why we make an exemption for modern artists and
museums, who live off self-promotion.