WordPress Version: 6.4
/**
* Registers an image size for the post thumbnail.
*
* @since 2.9.0
*
* @see add_image_size() for details on cropping behavior.
*
* @param int $width Image width in pixels.
* @param int $height Image height in pixels.
* @param bool|array $crop {
* Optional. Image cropping behavior. If false, the image will be scaled (default).
* If true, image will be cropped to the specified dimensions using center positions.
* If an array, the image will be cropped using the array to specify the crop location:
*
* @type string $0 The x crop position. Accepts 'left' 'center', or 'right'.
* @type string $1 The y crop position. Accepts 'top', 'center', or 'bottom'.
* }
*/
function set_post_thumbnail_size($width = 0, $height = 0, $crop = false)
{
add_image_size('post-thumbnail', $width, $height, $crop);
}