Description:
------------
It seems that php misparses string expressions that begins with 'ads_'.
The following code shows how two images, one with filename starting by 'ads_' is not displayed, while the same image with filename starting by 'adse_' is displayed. 

Test script:
---------------
<html>
 <head>
  <title>PRACTICA ADSORCION</title>
 </head>
 <body>

<?php
	$counter = "1167";
        $picture = "<img alt='ads_$counter.png' src='./images/ads_$counter.png' width=480 height=480 >";
  	print $counter;
  	print $picture;
	$counter = "1179";
        $picture = "<img alt='adse_$counter.png' src='./images/adse_$counter.png' width=480 height=480 >";
  	print $counter;
  	print $picture;
?>
</br>

</body>
</html>


Expected result:
----------------
Two images should have been displayed.

Actual result:
--------------
Only one image is displayed.
No image with prefix 'ads_' can be displayed.