Custom Image Sizes Radio Buttons in Wordpress Media Uploader

if ( function_exists( 'add_image_size' ) ) {
    add_image_size( 'twelve-columns', 1150, 1150, false );
    add_image_size( 'ten-columns', 950, 950, false );
    add_image_size( 'eight-columns', 750, 750, false );
    add_image_size( 'six-columns', 550, 550, false );
    add_image_size( 'four-columns', 350, 350, false );
    add_image_size( 'two-columns', 150, 150, false );
}
// origin: http://sumtips.com/2011/12/custom-image-sizes-in-wordpress.html
// modified
function mxdCustomImageSizes($sizes) {
    unset( $sizes['thumbnail']);
    unset( $sizes['medium']);
    unset( $sizes['large']);
    //~ unset( $sizes['full'] ); // removes full size if needed

    $myimgsizes = array(
        'twelve-columns' => __( '12 columns' ),
        'ten-columns' => __( '10 columns' ),
        'eight-columns' => __( '8 columns' ),
        'six-columns' => __( '6 columns' ),
        'four-columns' => __( '4 columns' ),
        'two-columns' => __( '2 columns' )
    );
    // if 'full size' is also unset, don't merge arrays but return $myimgsizes instead!
    if( !empty($sizes) )
        return array_merge($sizes, $myimgsizes);
    else
        return $myimgsizes;
}
add_filter('image_size_names_choose', 'mxdCustomImageSizes');