Override WordPress [gallery] shortcode with your own shortcode

Overriding the [gallery] is simple. Below you’ll find a snippet that overrides it with a custom implementation. You can use the same method to override any of the built-in shortcodes, such as [audio], [video] and [caption].

//Init hook
add_action('init', 'override_gallery');

//Override function
function override_gallery()
{
    remove_shortcode('gallery');
    add_shortcode('gallery', 'my_gallery_shortcode');
}

//Custom gallery shortcode
function my_gallery_shortcode($atts, $content) {

    //Default parameters to 
    extract( shortcode_atts( array(
            'ids' => '',
            'orderby' => 'post__in',
            'columns' => '3',
            'link' => 'file' //file | link | <empty string> (for linking to attachment page)
    ), $atts ));

    //Your own presentational code here...
}