It is very common to upload a wrong featured image accidentally.
It happens a lot to me.
In that case, click on the “Replace Image” button located inside the “Featured image” section:
The “Replace Image” button will open up the media library again.
If the replacement image is not already uploaded to the media library, upload the new image and set it as a featured image.
For some reason, if you remove the featured image completely, click on the “Remove featured image” link.
Anyway, that’s all you need to know about featured images for now.
In the next lesson, we will discuss taxonomies in WordPress.