I’m having the same issue, but I don’t have the same settings, as I’m working with a single WordPress install and not Multi-site like in Clement35’s picture. So, I can’t find where to change the uploader settings. I assume this is what I need to do, since it worked for so many others. Where can I find this setting?
Using WordPress 3.2.1 with the Striking theme and the Custom Post Type I made using the Custom Post Type UI does not have the Featured Image box shown. I did add the code to enable post-thumbnails for my theme.
