<img src='./php/getfile.php?file=xyz-thumb.jpg'></a>

// File Exists?
    if( file_exists($fullfilename)){

        // Parse Info / Get Extension
        $fsize = filesize($fullfilename);
        $path_parts = pathinfo($fullfilename);
        $ext = strtolower($path_parts["extension"]);

        // Determine Content Type
        switch ($ext) {
            case "pdf": $ctype="application/pdf"; break;
            case "exe": $ctype="application/octet-stream"; break;
            case "zip": $ctype="application/zip"; break;
            case "doc": $ctype="application/msword"; break;
            case "xls": $ctype="application/vnd.ms-excel"; break;
            case "ppt": $ctype="application/vnd.ms-powerpoint"; break;
            case "gif": $ctype="image/gif"; break;
            case "png": $ctype="image/png"; break;
            case "jpeg":
            case "jpg": $ctype="image/jpg"; break;
            default: $ctype="application/force-download";
        }

        header("Pragma: public"); // required
        header("Expires: 0");
        header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
        header("Cache-Control: private",false); // required for certain browsers
        header("Content-Type: $ctype");

        if ($mode == "view"){
            // View file
            header('Content-Disposition: inline; filename='.basename($fullfilename));
        }
        else {
            // Download file
            header('Content-Disposition: attachment; filename='.basename($fullfilename));
        }

        header("Content-Transfer-Encoding: binary");
        header("Content-Length: ".$fsize);
        ob_clean();
        flush();
        readfile( $fullfilename );

    } else
        die('File Not Found:' . $fullfilename);

./php/getfile.php?file=xyz-thumb.jpg

./files/usBmN5CssIL47qRroC77n90juaQoREThBbFZUddGneEH5jOuX6JpU5cH6zH1Xa5-thumb.jpg