在php中用正则表达式删除img标签的width、height、style

<?php
$txt1='<a href="http://www.aiweik.com/index.php?m=home&c=newsdetail&a=index&id=1812337" style="margin:0 auto;border-radius:6px; background-color: #ffb808;display: block;text-align: center;padding: 12px 12px 12px 12px;color:#fff; width: 180px;font-weight: bold;">查看历史中奖记录</a><img src="http://my.cqtimes.cn/Uploads/ueditor/image/20170512/1494556977462196.jpg" title="1494556977462196.jpg" alt="timg.jpg" style="width: 524px; height: 689px;" width="524" height="689"><img src="http://my.cqtimes.cn/Uploads/ueditor/image/20170512/1494556977462196.jpg" title="1494556977462196.jpg" alt="timg.jpg" style="width: 524px; height: 689px;" width="524" height="689">';

$txt1 = preg_replace( '/(<img.*?)(style=.+?[\'|"])|((width)=[\'"]+[0-9]+[\'"]+)|((height)=[\'"]+[0-9]+[\'"]+)/i', '$1' , $txt1);

echo $txt1;
?>