php正则替换 img使用lazyload

html内容中的

替换成

<?php 
$loadimg = 'load.jpg';
$str = '<img src="images/1.jpg" imgtype="upload" />';
$pattern = '/^(<img.*)src=([\'|\"])(.*)([\'|\"])(.*)$/i';
$replacement = '$1src=$2'.$loadimg.'$4 url=$2$3$4$5';
$str1 = preg_replace($pattern, $replacement, $str);
echo( $str1 );
?>