Dirty Pictures

With a voice that sounds like a more mainstream version of the late jazz cult superstar Eva Cassidy and smoky raven-haired looks to rival a movie lot's worth of young ingénues, it's a bit of a surprise that Katie Melua has remained so unknown in the United States, despite the chart success the Eastern European-born songstress has achieved in her adopted home of the United Kingdom. It seems like she should be at least as popular as, say, Regina Spektor or Nellie McKay. Pictures may not help that much, however, because in comparison to its fairly straightforward jazz-tinged singer/songwriter predecessors, Melua's third album takes a bit of a left turn into the self-consciously quirky. It's a wonder that it took so long, because Melua's producer and part-time songwriter is Mike Batt, a minor legend of the U.K. music scene who has fashioned a decades-long career out of deliberate eccentricity…