I noticed in the past that some images went missing from blog entries. That’s due to an error in the image URL. For some reason it changes to https instead of http. Since I didn’t want to pay for a SSL certificate I’m currently using a self-signed one – which every browser regards as not trustworthy. Well yes it isn’t trustworthy but I still want to use TLS when logging into the Admin Panel as I don’t want to send my password in clear text.
So I set a special variable in the wp-config.php file as described here: http://codex.wordpress.org/Administration_Over_SSL
For some reason though, WordPress uses https for image URLs as well after I update some plugins or WordPress itself. I haven’t found a permanent solution yet, so if you know how to fix this, please let me know.