The Featured Image, or post thumbnail, is a feature in a WordPress theme that gives theme developers the ability to add support for utilizing a representative image for pages, posts, or custom post types. Featured Image is the official term used for this WordPress feature; however, there are still some template tags and functions that use post thumbnail instead of featured image. The motivation behind changing the term to “featured image” from “post thumbnail” was partly due to the fact that “post thumbnail” did not fully describe the ability to customize the representational image. Despite “featured images” being the term of choice for this feature in WordPress, the featured images page in the WordPress Codex is still titled “Post Thumbnails.”
In order to add featured image support into a theme, WordPress developers can simply add a snippet into the functions.php file for their theme. In addition, there is a way to configure the handling of image uploads by WordPress. Authors can select the size of thumbnails, style them, and turn the display ON and OFF for featured images. The how and the where for the image display will be different depending on the theme.
There are many examples of the uses of featured images. One such example is that featured images are used by several WordPress photography themes in their layout. In addition, the front pages of entertainment and news websites powered by WordPress have included thumbnail images with each article.
By clicking the “set featured image” link in the Post Edit Screen, users are able to directly upload the images. When no image is found, authors can also set a default image for display. If you are having trouble locating the “set featured image” link, look in the top right of the admin panel under screen options and ensure it is enabled.