I know, WP doesn't recommend downgrading. But I need my site to work again RIGHT NOW, and the 3.5 upgrade has completely broken the ability for the front page of my news website to show thumbnails of new stories. I can't let that go on, and so far I haven't been able to make thumbnails work and haven't had any action on my post about the thumbnail/upgrade problem (I explain the problem in detail there): http://wordpress.org/support/topic/35-broke-post-thumbnails-for-all-new-posts?replies=2
In brief, http://oceanbeachbulletin.com is using WP 3.5 with Mimbo 3.0 theme, hosted on Laughing Squid. The problem is that since the upgrade, no thumbnails of images from posts are showing up on the front page. On individual post pages everything seems fine, but the thumbnails of images from new posts won't show up. All the thumbnails of pre-upgrade posts still work fine.
I've seen a few other posts about downgrading from 3.5 but none of them seem to address what appears to be the need to downgrade the database, which got upgraded as well.
Can anyone help with step-by-step instructions for downgrading to the previous version of WordPress, including any downgrades of the database?
I'm annoyed at WP because we were forced to upgrade - we couldn't access the admin until we did - and now a perfectly working website has this costly and embarrassing problem because of it. But I'm hopeful that we'll be able to use 3.5 eventually because I actually like what I see of it. For right now, though, I just need my site to work again ASAP.