Kindle .mobi to .epub - image zooming & navigation

[hegi]

Hi guys,
due to Amazon no longer accepting .mobi via email, I changed my kindle readstuff sent from calibre to .epub this summer.

However, what still bugs me is, that
(1) before I could click on images and they enlarged and turned 90° to use maximum width of the display. - Now they enlarge a litte, but as they are not turned, this is only 5-10% bigger. Is this due to the limitiatons of the format, or requires this editing of the recepies?

(2) Naviagtion works perfectly in Calibre-reader, but in the kindle, from the article view the buttons for the sections and the article list do not seem to work. - This applies for mulitple recipes.

I do not think, that this are limitations to the format. - Is this just amazon implementing a poor .epub interpretation, as this is a competetive file-format?

Thanks a lot & take care
Hegi.