Adds the ID col

media-uploader-tweak.php

<?php

Class MediaUploaderTweak {

    static function run() {
        add_filter( 'manage_media_columns',  array( 'MediaUploaderTweak', 'cols' ), 1 );
        add_action( 'manage_media_custom_column', array( 'MediaUploaderTweak', 'col' ), 1, 2 );
        add_action( 'admin_head-upload.php', array( 'MediaUploaderTweak', 'admin_head' ) );
    }

    // Does some basic re-ordering and adds new column. 
    static function cols( $defaults ) {

        // Define new array to store columns 
        // (need to merge the ID in after the icon. 
        $new_array = array();
        $new_array[ 'cb' ] = $defaults[ 'cb' ];
        $new_array[ 'icon' ] = $defaults[ 'icon' ];
        $new_array[ 'attachment_id' ] = __( 'ID' );

        // Remove these two as we've added in manually. 
        unset( $defaults[ 'cb' ] );
        unset( $defaults[ 'icon' ] );

        // Merge anything in else that may exist.
        return array_merge( $new_array, $defaults );
    }

    // If correct, adds the ID 
    static function col( $column_name, $id ) {
        if ( $column_name === 'attachment_id' ) {
            echo $id;
        }
    }

    // Sets the width on the col 
    static function admin_head() {
        echo '<style type="text/css"> #attachment_id {width: 40px; } </style>';
    }
}

MediaUploaderTweak::run();