Just an FYI that version 1.8.0 made the feature image function disappear for me using Themeforest’s Lotus. There was no problem with version 1.7.2. WordPress 4.2.2.
Just a follow-up to this, in case anyone comes afterwards with a similar problem and wonders what the outcome was.
The problem was not a character set and collation mismatch. It was the magic_quotes settings in the PHP.ini file. My ISP had them set to ON, but that was incompatible with WP. I asked them to turn them off and it immediately solved the problem.
