Dump WP image resize information

wpse17728.php

<?php
/*
Plugin Name: WPSE 17728
Plugin URI: http://wordpress.stackexchange.com/questions/17728/large-image-size-is-cropped-not-proportional
Description: Large image size is cropped, not proportional?
Author: jimilesku
*/

add_filter( 'intermediate_image_sizes_advanced', 'wpse17728_intermediate_image_sizes_advanced' );
function wpse17728_intermediate_image_sizes_advanced( $sizes )
{
    var_dump( $sizes );
    return $sizes;
}