Add an icon to the featured image HTML - Genesis

post.php

<?php namespace tonya;

remove_action( 'genesis_entry_content', 'genesis_do_post_image', 8 );
add_action( 'genesis_entry_header', 'tonya\do_post_grid_image', 1 );
/**
 * Echo the post image 
 *
 * @since 1.1.0
 *
 * @uses render_post_featured_image()
 */
function do_post_grid_image() {
    if ( ! is_singular() && genesis_get_option( 'content_archive_thumbnail' ) ) {
        \tonya\render_post_featured_image( 'grid_thumbnail', 'grid-thumbnail' );
    } else {
        \tonya\render_post_featured_image( 'post_featured_image', 'post-featured-image' );
    }
}

/**
 * Adds the respective icon to the image's HTML
 *
 * @since  1.0.0
 * 
 * @param  string $size 
 * @param  string $class
 * @return void
 */
function render_post_featured_image( $size, $class ) {
    $img = genesis_get_image( array(
        'format'  => 'html',
        'size'    => $size,
        'context' => 'archive',
        'attr'    => genesis_parse_attr('entry-image'),
    ));

    if ( ! empty( $img ) ) {
        $icon = 'icon-large-' . get_post_type( get_the_ID() );
        echo apply_filters( 'tonya_post_grid_image_filter', 
            sprintf( '<div class="%s"><a href="%s" title="%s"><span class="%s"></span>%s</a></div>', 
                esc_attr( $class ), 
                get_permalink(), 
                the_title_attribute( 'echo=0' ), 
                $icon,
                $img
            )
        );
    }
}