This script blocks oEmbed

How can this script block oEmbed?
It is an auto-embed image script. It gets the url of the image and converts it into an image.

function content_magic($content) { 

$content = get_the_content();

$m= preg_match_all('!http://[a-z0-9\-\.\/]+\.(?:jpeg|jpg|png|gif)!Ui' , $content , $matches);

if ($m) {
 $links=$matches[0];
 for ($j=0;$j<$m;$j++) {
 $content=str_replace($links[$j],'<img src="'.$links[$j].'">',$content);
 }
 }

 return $content;
 }
 add_filter('the_content','content_magic');

How can I solve this Problem?
Thank you in advance,
Chief