See on Wordpress.org.
Download Post Thumbnail Extras and unzip it to your
directory. Alternately, use Wordpress’ plugin updater to automatically install
the stable version.
Use the shortcode
[pt] in your posts to quickly embed the featured image as a
thumbnail. Use the attribute
'size' to change to a different post-thumbnail
[pt size='medium']). You can also use any image in your media
gallery if you know the id, by using the
id attribute (
link attribute to wrap the image in a link.
link='file'will create a link to the full size image.
link='post'will create a link to the attachment page.
link='http...'creates a link to any URL.
Use the media library to quickly add this shortcode for the selected image by
pressing the “Insert shortcode” button.
In Settings → Media, click the plus sign to add a new post thumbnail.
Update the width/height and whether or not the post-thumbnail should be
cropped to an exact size. (If the width or height is set to 0, that boundary
constraint is not enforced – effectively, it’s infinite). Make sure you
click the “save” button so that the changes are stored in the database.
If you want to report an issue:
If you’ve found this plugin valuable in any way, consider donating to my tip jar. (This is so my wife doesn’t murder me for staying on the computer too late. :D)