I don't hold that a painting must be beautiful to be great. But I also think that great paintings are far more often beautiful than not. Moreover, I find it difficult to think that really ugly paintings are great ones.
There are always a few exceptions, but not the ones of women by Pablo Picasso and Willem de Kooning featured here. The art world seems to disagree with me because the Picassos auctioned for many tens of millions of dollars, and the de Koonings aren't worth chicken feed either.
First, two Picasso paintings -- the first, a portrait of one woman, the second showing women. Then two de Koonings in the same sequence.
An auction sale report is here.
A report for this painting of a bordello is here.
As the numeral implies, de Kooning painted a series dealing with women.
Picasso's paintings are more structured than de Kooning's, the Algiers being almost cheerful.
Borderline ugly, I'd call it. The Dora Maar is just plain awful so far as I'm concerned, though I'll credit Picasso for doing a reasonably good job on the kitten. I find the de Koonings simply horrible. His apologists would praise the emotion and artistic action seen in his brushwork. A lot of emotion does not guarantee a painting's greatness. Here, ugliness rules.