I installed Simple Auto Featured Image on a blog that has several thousand posts that use a custom post type. About half the posts contain images inserted using <img> tags pointing at image URLs on the same domain.
I configured the plugin to generate featured images for the custom post type and pressed the save button. Nothing happened and none of the posts seem to have featured images set.
It seems like there should be a Generate button somewhere but I can't find it. What am I doing wrong?