RERULER EXPRESSION

http://www.catswhocode.com/blog/15-php-regular-expressions-for-web-developers
http://phpvn.info/2007/07/regular-expression
xoa nhung the a co src=''

$html = '<img src="adasas.jpg" /><br />asasas<br />sdfsdf<br /><a href="adafgag"><img title="asa" src="" /></a>';

'!(<a\s[^>]+>)?<img([^>]+)src=""([^>]*)>(</a>)?!i'