Parse through wordpress post content and update the image source URLs to lowercase

function.php

<?php
//http://wordpress.stackexchange.com/questions/104605/update-image-path-with-words-starting-uppercase-to-lowercase-chars
//make located image source lowercase
function replace_cb($matches) {
	if (!empty($matches[1])) {
		return 'src="'.strtolower($matches[1]).'"';
	} else {
		return $matches[0];
	}
}

//Query all the post content and parse image source to make it lowercase
function update_src_case(){
	global $wpdb;

	$posts = $wpdb->get_results("SELECT ID,post_content FROM {$wpdb->posts} WHERE post_type='post'");
	$pattern = '/src="([^"]*)"/i';

	foreach ($posts as $p) {
		define( 'DOING_AUTOSAVE', true );
		$p->post_content = preg_replace_callback( $pattern, 'replace_cb', $p->post_content );
		//var_dump($p->post_content);
		wp_update_post($p);
	}

}
update_src_case();