Display Post Thumbnail Also In Edit Post and Page Overview in admin panel

For this here I'll tell you two Technics. One by Plugins and second by adding some code in Functions.php file .

Technic 1: Simply Download this plugins and activate

You can download from here:  click here to download

Technic2:  Paste this below code into functions.php file 

if ( !function_exists('fb_AddThumbColumn') && function_exists('add_theme_support') ) {
 
 // for post and page
 add_theme_support('post-thumbnails', array( 'post', 'page' ) );
 
 function fb_AddThumbColumn($cols) {
  
  $cols['thumbnail'] = __('Thumbnail');
  
  return $cols;
 }
 
 function fb_AddThumbValue($column_name, $post_id) {
   
   $width = (int) 35;
   $height = (int) 35;
   
   if ( 'thumbnail' == $column_name ) {
    // thumbnail of WP 2.9
    $thumbnail_id = get_post_meta( $post_id, '_thumbnail_id', true );
    // image from gallery
    $attachments = get_children( array('post_parent' => $post_id, 'post_type' => 'attachment', 'post_mime_type' => 'image') );
    if ($thumbnail_id)
     $thumb = wp_get_attachment_image( $thumbnail_id, array($width, $height), true );
    elseif ($attachments) {
     foreach ( $attachments as $attachment_id => $attachment ) {
      $thumb = wp_get_attachment_image( $attachment_id, array($width, $height), true );
     }
    }
     if ( isset($thumb) && $thumb ) {
      echo $thumb;
     } else {
      echo __('None');
     }
   }
 }
 
 // for posts
 add_filter( 'manage_posts_columns', 'fb_AddThumbColumn' );
 add_action( 'manage_posts_custom_column', 'fb_AddThumbValue', 10, 2 );
 
 // for pages
 add_filter( 'manage_pages_columns', 'fb_AddThumbColumn' );
 add_action( 'manage_pages_custom_column', 'fb_AddThumbValue', 10, 2 );
}