Automatically sets the featured image (previously named post thumbnail) to the first uploaded image into the post. So easy like that...
WordPress installs below 3.7 are not supported. But you can use Easy Add Thumbnail 1.0.2 if you use WordPress 2.9 or higher
No. This plugin uses only standard WordPress functions to set the featured image. And using this standard (and friendly) method WordPress simply has not any knowing about images not attached to the post.
As stated above this plugin uses standard WordPress method to set the featured image, this does not include any size information. The size used by your theme for displaying image thumbnails depends totally on how your theme was coded.
Contact to your theme author for support if you're having this problem.
Yes. When I released first version of this plugin years ago, featured images was named as post thumbnails, but later WordPress team decided to change the name to "featured image".
In fact, WordPress core functions for featured image, still uses original thumbnail names.
That's because the plugin name (that can't be changed in the Extend directory without having issues) says "thumbnail".
I did it to fullfil the needs of many of my WordPress maintenance service customers.
At first not. The main and only purpose of this plugins is to do what it already does right now.