How to set an featured image for an article that does not have an featured image

I installed Easy Add Thumbnail so that the first image appearing in a post becomes the featured image. After that, I installed a plugin called Quick Featured Images. This plugin allows you to set featured images in bulk for existing posts and also set them for future posts. With this plugin, you can assign specific featured images based on categories or tags, so I set a featured image for all categories and also for future posts.

With these two plugins, 96% of the posts now have featured images, but 4% still do not. The issue is with the posts where Easy Add Thumbnail didn’t pick up the image as a featured image, even though it existed within the post. For these remaining posts, I installed a plugin called Auto Featured Image (Auto Post Thumbnail) to generate featured images and avoid leaving any “No Images” placeholders. However, the featured images created by Auto Featured Image seem somewhat rough or odd, so I plan to fix them in the future.