Erledigt...

falls es jemanden interessiert oder wer was besseres weiss -

preg_match_all("/\<img(.*)\/>/iUs", $z[1], $matches);  
			$bx=count($matches[0]);  
			if($bx > 0){  
				$b1 = explode("<img",$z[1]);  
				$z[1] = "$b1[0]";  
				$z[1] = str_replace("".$_GET["s"]."","<span class=\"searchValue\">".$_GET["s"]."</span>",$z[1]);  
				for($g = 1; $g <= $bx; $g ++){  
					$b2 = explode("/>",$b1[$g]);  
					$z[1] .= "<img $b2[0] />";  
					$z[1] .= str_replace("".$_GET["s"]."","<span class=\"searchValue\">".$_GET["s"]."</span>",$b2[1]);  
				}  
			}  
			echo"$z[1]";