zawp-example-functions.php

/**
 * Get Image URL.
 *
 * @param integer $id   ID of the image.
 * @param string  $args The image arguments.
 *
 * @return string The image URL.
 */
function zawp_get_image_url( $id, $args ) {
	// If image returned is an array, then return it's 'ID'.
	if ( is_array( $id ) ) {
		$id = $id['ID'];
	}

	// perform any additional checks here, based on data passed in the $args array.
	// Return an empty string if any of the checks fail.

	// Get image source.
	$img = wp_get_attachment_image_src( $id, $args['size'] );

	// perform any additional checks here, based on the returned img array.

	// Return the image URL, or an empty string.
	return ! empty( $img ) && is_array( $img ) ? $img[0] : '';
}

/**
 * Render image container.
 *
 * @param array $image_id The image id.
 * @param array $args The image arguments.
 */
function render_image_url( $image_id, $args ) {
	$img_url = zawp_get_image_url( $image_id, $args );
	echo '<div class="featured"><img src="' . esc_url( $img_url ) . '" alt="Featured image"></div>';
}

// how to call the render_image_url function in theme templates
render_image_url( 123, array( 'size' => 'full' ) );