/**
 * Enable post thumbnails.
 */
if ( function_exists( 'add_theme_support' ) ) { 
	add_theme_support( 'post-thumbnails', array( 'project' ) ); // Add support for posts
	add_image_size( 'large-feature-image', 715, 402, true ); // large size, hard crop mode
}

This snippet adds support for post thumbnails (a.k.a. 'featured images') to a Wordpress theme. It also adds an additional image size for image thumbnails, hard cropped. This second step is optional.

Add this snippet to your WP theme's functions.php file.

Enable post thumbnails for a Wordpress theme

wordpress, images

PHP