Some Kindle eBooks are now "Optimized for Kindle DX"

Amazon-optimized-for-DX-badge Karen at the excellent Books on the Knob blog notes in a post today that some books in Amazon’s Kindle Store are now marked as "Optimized for Kindle DX":

Will those who use a KindleDX get the same book and just have more screen real-estate for viewing pictures and charts… Or will those with a KindleDX get an entirely different book, with pictures, tables and other layout features omitted from the basic reader device versions?

That is a very good question. We presume that the answer will be clear by late next week as customers begin experimenting with the DX.

Amazon’s offers a short explanation for the "Optimized for Kindle DX" logo in an adjacent pop-up window:

This title has complex layouts and has been optimized for reading on Kindle DX’s larger screen, but can still be viewed on other devices.

Karen’s post also suggests a question. If an Amazon customer has previously purchased a Kindle book that is now available in updated format as "Optimized for Kindle DX", will the customer have to buy the book again to read the DX-optimized format on a brand new Kindle DX?