image-sizes-fix.php

<?php
/**
 * Add image sizes to Insert Into Post list
 * @see http://goo.gl/CJdR4
 *
 * @param array $sizes
 * @return array
 */
add_filter('image_size_names_choose', 'display_image_size_names', 11, 1);
function display_image_size_names($sizes)
{
    $new_sizes = array();
    
    $added_sizes = get_intermediate_image_sizes();
    
    // $added_sizes is an indexed array, therefore need to convert it
    // to associative array, using $value for $key and $value
    foreach( $added_sizes as $key => $value) {
        $new_sizes[$value] = ucwords(str_replace('-', ' ', $value));
    }
    
    // This preserves the labels in $sizes, and merges the two arrays
    $new_sizes = array_merge( $new_sizes, $sizes );
    
    return $new_sizes;
}