Below code for sameple custome page reading query.
Post Thumbnail URL Finding :

<?php //$mini_tennis_rewards_thumb = get_the_post_thumbnail($mini_tennis_rewards_data->ID, array(63,63));
$mini_tennis_rewards_thumb_src = wp_get_attachment_image_src( get_post_thumbnail_id( $mini_tennis_rewards_data->ID ), “thumbnail” );
?>

<a href=”<?php echo get_permalink($mini_tennis_rewards_data->ID); ?>”><img src=”<?php echo $mini_tennis_rewards_thumb_src[0]; ?>” /><span><?php echo $mini_tennis_rewards_data->post_title; ?></span></a>

<?php
$page_name = array(134,4778,4780,4782,4784,4786);

$privateCoaching_data = get_page($page_name[0]);
$proVideos_data = get_page($page_name[1]);
$calendar_data = get_page($page_name[2]);
$tipsOfTheWeek_data = get_page($page_name[3]);
$juniorPathway_data = get_page($page_name[4]);
$adultPathway_data = get_page($page_name[5]);
?>
<h1><a href=”<?php echo get_permalink($privateCoaching_data->ID); ?>”>Private Lessons</a></h1>

<img src=”<?php bloginfo( ‘stylesheet_directory’ ); ?>/images/privateLessons.jpg” />
<a href=”<?php echo get_permalink($privateCoaching_data->ID); ?>”><img src=”<?php bloginfo( ‘stylesheet_directory’ ); ?>/images/read-more.jpg” border=”0″ /></a>
<?php
//$privateCoaching_data_content = apply_filters(‘the_excerpt’, $privateCoaching_data->post_excerpt); // Get Content and retain WordPress filters such as paragraph tags. Origin from: http://wordpress.org/support/topic/get_pagepost-and-no-paragraphs-problem
//echo $privateCoaching_data_content;
echo $privateCoaching_data->post_excerpt;
?>

<!– Below line showes the post image –>

<?php echo get_the_post_thumbnail($mini_tennis_rewards_data->ID, ‘full’); ?>

This is line shows only for Image URL :

$thumbnail_src = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), "size" );

this is useful for custom post reader or page reader purpose.