I have 2 websites, built along similar styles and themes, and illustrating a 'before' and 'after' view of this issue:
this is the one where the slide images disappeared from the home page, after I downloaded v3.6 and entered WP admin to edit copy. I did no edits, because the Dashboard looked completely different, and the window showing text & photos in the Edit Portfolio Project displayed code instead of photos. This perplexed me, so I went to "Home" page and discovered the slide images were gone.
Here is the other website, still on the old WP version, as I have not entered this site's "Admin" yet to make any changes. Its slide images are visible on its Home page:
If you have any ideas, thanks for your help. meanwhile I posted a new forum thread but have no helpful responses.