I just tried it and it worked ok for me.
I select the artist I want and I am shown the front, back and a disk.
I click on the back and another page opens showing me the front at the top but if I scroll down under cover info I find a picture of the back with download below it. If I click download I get an enlarged picture of the back.
If you play around with the page you need to get the picture you want with 'download' below it.
You have a play around and see how you get on.