interfacer

Hi All :)  I recently just purchased a book on OOP in PHP 5 and have been working through it.  I ran into a wall when I've been trying to use an imageOnly() method to sort out any non image files before they are displayed.  Here is the constructor: [code]  public function __construct($directory, $replacechar = "_") {     $this->directory = $directory;     $this->replacechar=$replacechar;     $d="";     if(is_dir($directory)){     $d = opendir($directory) or die("Couldn't open directory.");     while(false !== ($f=readdir($d))){       if(is_file("$directory/$f")){       $this->filearray[] = $f;       }     }     closedir($d);     }else{     //error     die("Must pass in a directory.");     }   }[/code] Here's the imageOnly() method: [code]  public function imagesOnly(){     $extension = "";     $types = array("jpg", "jpeg", "gif", "png");     foreach($this->filearray as $key => $value){     $extension = substr($key,(strpos($key, ".") + 1));     $extension = strtolower($extension);     if(!in_array($extension, $types)){       unset($this->filearray[$key]);     }     }   }[/code] and finally, here's what I'm trying to output it with: [code]<? require 'DirectoryItems.php'; $directory = "test"; $di = new DirectoryItems($directory); $di->naturalCaseInsensitiveOrder(); $di->imagesOnly() or die("imagesOnly() isn't working"); $filearray=$di->getFileArray(); echo "<div style=\"text-align: center;\">"; foreach($filearray as $key => $value) { echo "<img src=\"test/$value\"><br />\n"; } echo "</div><br />"; ?>[/code] My class file is named as DirectoryItems.php. if I take out the imagesOnly line, it works fine as long as there are no non-image files in my directory.  Any help in assessing why that method is causing it to appear as "imagesOnly() isn't working" would be wonderful.  Thank you all for your help, I sincerely appreciate it.