There should have been a huge outcry by now. Government ministers and artists and academics and journalists should be shouting from their pulpits. Because a unique part of South Africa's cultural heritage was stolen this week. The work of one of the country's foremost artists. Five years of images lost - many of them irreplaceable. But hardly a word. Why? Because what was stolen was a collection of photos taken by Zanele Muholi - stunning, striking, powerful images of black lesbians and of gay, bisexual, transgender and intersex people and the prejudices they face.