Since version 2.9 of WordPress, it’s been possible to have post thumbnails. Once these thumbnails have been set, they can be used throughout your site whenever your post is called. Using post thumbnails is easy, and so is enabling them. It’s only a few steps, so let’s get started.
The first step to using post thumbnails in WordPress is to enable them. To do that, all you need to do is put the following in you themes functions.php file.
Once you’ve added this code, you should see a box underneath “Post Tags” in the Edit Post screen.
Set the Post Thumbnail
Now that you have the featured image box in you WordPress Edit Post area, you need to click the “Set featured image” link. Once you do that, you’ll be greeted with the usual WordPress image upload screen. Select the image you would like to upload, and then let WordPress do it’s image crunching magic. Now comes the most important part, you need need to click “Use as featured image”.
Obviously post thumbnails aren’t much use to you if nobody can see them. To see them in your theme, you need to call the following function while inside The Loop.
<? the_post_thumbnail(); ?>
That’s it! It’s now easier than ever you have each one of your posts have a thumbnail. If you have any questions, please leave them in the comments.