<?php function youtubebuyut($gelen){
$istenmeyen= array('/s100-c-k-no-mo-rj-c0xffffff');
$degisen = array('');
$giden = str_replace($istenmeyen,$degisen,$gelen);
return $giden;
}
$link = 'https://yt3.ggpht.com/-5Pt7wtAZ6o0/AAAAAAAAAAI/AAAAAAAAAAA/SVN1romJpFw/s100-c-k-no-mo-rj-c0xffffff/photo.jpg';
echo '<img src="'.youtubebuyut($link).'" alt="Youtube" height="500" width="500">';
?>Çıktı: 
