If you go to Simon and Schuster's website, the Hardy Boys that are available as ebooks now have high-quality jpeg covers. For example:
(https://d28hgpri8am2if.cloudfront.net/book_images/onix/cvr9781439121610/darkness-falls-9781439121610_hr.jpg)
(https://d28hgpri8am2if.cloudfront.net/book_images/onix/cvr9781534456297/dead-on-target-9781534456297_xlg.jpg)
(https://d28hgpri8am2if.cloudfront.net/book_images/cvr9781481421966_9781481421966_hr.jpg)
(https://d28hgpri8am2if.cloudfront.net/book_images/cvr9781481421973_9781481421973_hr.jpg)
(https://d28hgpri8am2if.cloudfront.net/book_images/cvr9781481421980_9781481421980_hr.jpg)
Nice! Thanks for the tip. :) 8)