ah, yes, no the line breaks are gone :-) Good! (And yes, it's expected that the size of the text field returns to its original size, this is not a problem.)
There was a very similar problem a few days ago: http://wordpress.org/support/topic/plugin-wp-table-reloaded-insert-image-wont-except-html-code
It seems that the Amazon scripts show some weird/wrong behavior at this time...
Oh, and I also checked the site which shows what you want to achieve: They do this in a different way (without the not-working script): They directly embed the images and then add the buttons as direct links to the Amazon pages (with their affiliate ID included of course).