User blog comment:Sarah Manley/New Editor Scheduled for Sitewide Release/@comment-1430834-20110831134715/@comment-126761-20110831135254

Generally it should pick the first suitable image in the page. I believe manual tweaks are being considered, but it's generally better to make sure the magic picker works without manual tweaks - if you've got examples where it's failing to pick something suitable, do send them along to Special:Contact, and we can look to see what could be done.