hi,
how find in text only one image?
$text = 'text text <img src = "http://physics.unl.edu/dept/directories/images/gradpics/Cat.jpg" /> text text <img src = "www.url.com/image.gif" />';
preg_match_all('#http:[^<\s>]+[.](gif|png|jpe?g)#i', $text, $all_img);
print_r($all_img);