That's because iPhone’s Safari browser allows mobile site developers to specify an icon to be put on an iPhone's home screen when a user bookmarks the site. If this icon is not specified, however, the iPhone creates a mini-screenshot of the browser's current page and uses that for a bookmark icon.
You can do the same with your Blueprint site. Since Yahoo!'s mobile homepage is built using the same technology as our site, you can surely implement your own bookmark icon as we do for ours. The trick is not yet documented, but we are happy to share it with you upfront:
http://mobile.yahoo.net/developer/blog/200...ini-screenshot/
Screenshot:
