root/releases/0.301/_files/icon.php

<?php

    // Download script
    // Usage: http://URL/{username}/files/{folder_id}/{file_id}/{filename}
    
    // Run includes
        require("../includes.php");
        
    // Initialise functions for user details, icon management and profile management
        run("userdetails:init");
        run("profile:init");
        run("files:init");
        
    // If an ID number for the file has been specified ...
    
        if (isset($_REQUEST['id'])) {
            $id = (int) $_REQUEST['id'];
            
    // ... and the file exists ...
            
            $file = db_query("select location, access, originalname from files where ident = $id");
            if (sizeof($file) > 0) {
                
                $file = $file[0];
                                
                    if (run("users:access_level_check",$file->access) == true) {

    // Send 304s where possible, rather than spitting out the file each time
                        $if_modified_since = preg_replace('/;.*$/', '', $_SERVER['HTTP_IF_MODIFIED_SINCE']);
                        
                        $tstamp = filemtime($file->location);
                        $lm = gmdate("D, d M Y H:i:s", $tstamp) . " GMT";
                        
                        if ($if_modified_since == $lm) {
                            header("{$_SERVER['SERVER_PROTOCOL']} 304 Not Modified");
                            exit;
                        }

    // Send last-modified header to enable if-modified-since requests
                        if ($tstamp < time()) {
                            header("Last-Modified: " . $lm);
                        }
                        
    // Then output some appropriate headers and send the file data!
    
                        $mimetype = run("files:mimetype:determine",$file->originalname);
                        if ($mimetype == false) {
                            $mimetype = "application/octet-stream";
                        }
                        if ($mimetype == "image/jpeg" || $mimetype == "image/png") {
                            $icon = url . "units/phpthumb/phpThumb.php?w=90&src=" . urlencode($file->location);
                            $mimetype = "image/jpeg";
                        } else {
                            $mimetype = "image/png";
                            $icon = path . "_files/file.png";
                        }

    // "Cache-Control: private" to allow a user's browser to cache the file, but not a shared proxy
    // Also to override PHP's default "DON'T EVER CACHE THIS EVER" header
                        header("Cache-Control: private");
                        
                        header("Content-type: $mimetype");
                        readfile($icon);
                        
                    }
                    
                }
            }

?>