How to make this script more efficient/shorter..

[Guest kilbad]

Below I have posted my gallery script, and wanted to know if the community would give me some feedback on how to make the actual code more efficient/shorter.  I am not a professional coder, so I wanted to take this opportunity to learn some new coding techniques.  The script works.  I just want to be doing things the best, most efficient way.

 

<?php
        
     $page = $_GET['page'];
     $album = $_GET['album'];
     $album_identification = file_get_contents("$root/photos/$album/id.txt");

     if ($page == "") {$page = 1;}
     if ($album == "") {$album="general";}

     if (file_exists("$root/photos/$album/thumbnails/small_thumbnail-0.jpg"))
          {} else {
          system("chmod -R 777 $root/photos/$album");
          $dir = "$root/photos/$album/";
          $num = 0;
          $type = ".jpg";
          foreach ( glob ( $dir . "{*.jpg,*.JPG}", GLOB_BRACE ) AS $file ){
               rename ( $file, $dir . sprintf("%04d", $start++) . $type );}
          system("mkdir $root/photos/$album/thumbnails");
          system("chmod -R 777 $root/photos/$album/thumbnails");
     }

     $number_on_each_page = 6;
     $number_of_files = count(glob("$root/photos/$album/*.jpg"));
     $number_of_pages = $number_of_files / $number_on_each_page;

     echo "\t\t\t<div class='photo_container'>\n";
     echo "\t\t\t\t~ ";

     for($i = 1; $i <= $number_of_pages; $i++){
          if($i == $page){
               echo("<span style='font-weight:800;'>".$i."</span> ");
               }else{
                    echo("<a href=\"$i\">$i</a> ");}
     }

     if(($number_of_pages / $number_on_each_page) < 1){
          if($number_of_files == $number_on_each_page) {} else {
               if($i == $page){
                    echo("<span style='font-weight:800;'>".$i."</span> ");
                    }else{
                    echo("<a href=\"$i\">$i</a> ");}
          }
     } 

     if (file_exists("$root/videos/$album")){
          echo " | <a href='$URL_root/videos/$album'>video</a> ";}

     echo "~";
     echo "<br />\n";

     $number = ($page * $number_on_each_page - ($number_on_each_page));
     for($i = 1; $i <= $number_on_each_page; $i++) {
          photo_thumbnail($album,$page,$number);
          $number++;
          }

     echo "\t\t\t</div>\n";

?>

 

Functions I include for that page from another file::

<?php

function buffer($number){
     global $buffer;
     if ($number < 10) {
     $buffer="000";} else {
     if (($number >= 10) and ($number <= 99)) {
     $buffer="00";} else {$buffer="0";}}
     }

function photo_thumbnail($album,$page,$number){
     global $root,$URL_root,$buffer;
     if (file_exists("$root/photos/$album/thumbnails/small_thumbnail-$number.jpg")) {
          echo "\t\t\t\t<a href='$URL_root/photos/$album/$page/$number'><img class='thumbnail' src='$URL_root/photos/$album/thumbnails/small_thumbnail-$number.jpg' height='188px' width='250px' alt='' /></a>\n";
          } else {
               buffer($starting_number);
               if (file_exists("$root/photos/$album/$buffer$number.jpg")) {
               system("chmod -R 777 $root/photos/$album");
               system("convert $root/photos/$album/$buffer$number.jpg -resize 250x -quality 100 $root/photos/$album/thumbnails/small_thumbnail-$number.jpg");
               system("chmod -R 555 $root/photos/$album");
               echo "\t\t\t\t<a href='$URL_root/photos/$album/$page/$number'><img class='thumbnail' src='$URL_root/photos/$album/thumbnails/small_thumbnail-$number.jpg' height='188px' width='250px' alt='' /></a>\n";}}
     }

?>

 

Thank you all so much for your help in advance!

 

Brendan