php gallery show 12 items per page

[grasshopper31]

In this php file im showing all the pictures in one folder (album), how can I show only 12 pictures at a time using request p, i started but dont know how to combine both together. Check where the number signs are. thanks in advance.

<?php

class gal_cms{

	private $dir_photos = 'photos/';
	private $dir_cache = 'photos/load/';
	private $imgPerPage = '12';

	function validImages($file){ #TODO: improve/modify according to array
    	$ext = array('jpg','jpeg','png','gif');
    	if(in_array(array_pop(explode(".", $file)),   $ext)){
    		return $image;
    	}
	}
	
	
	function randomThumbnail($albums_location){ #TODO: finish this function
	
	 //$images = scandir($albums_location);
	 //$i = rand(2, sizeof($images)-1);
	$images = glob($albums_location . '*.{jpg,jpeg,png,gif}', GLOB_BRACE);

	$randomImage = $images[array_rand($images)];	
		return $randomImage; #TODO: get this image check for a thumbnail php generated then retrieve that picuture instead
	}
	

	
	function getContent(){
		echo '<h2>Photo Galleries</h2>'. 
		'<p>Here in Combbat 21, we like to capture the moments of all our memories. Whether it's during competitions or just being together as a team, we have a lot of fun times together. Time goes by really fast, so its best if you can remember all that you can. Pictures capture a moment and show them to you at a later time, reminding us of the fun seasons we had together.<br/><br/>Also check out our <a href="/">videos!</a>.</p><br/>';
					
	#TODO: short out this algorithm
		if(isset($_GET['year']) AND !empty($_GET['year'])){//year input -> check input
			$y = $_GET['year'];
			
			if(file_exists($this->dir_photos.$y)){//if correct year input -> check for 
				if(isset($_GET['album']) AND $_GET['album'] != ''){//year,album input -> check album input
				 	$album = $_GET['album'];
					if(file_exists($this->dir_photos.$y.'/'.$album)){
						$p = 'photos';
					} else {
						$p = '404';
					}
				} else {
					$p = 'albums';
				}
			} else {
				$p = '404';
			}

		} else {
			$p = 'years';

		}
		
		if($p == '404'){
			$sqlError = "SELECT * FROM articles WHERE id='104'";
				$result = mysql_query($sqlError) or die(mysql_error());
				while ($row = mysql_fetch_array($result)) {
			  		$page = array();
			  		$page['title'] = $row['title'];
			  		$page['content'] = $row['content'];
					
				//Be careful since content is all html
			    echo '<h2>'.$page['title'].'</h2>'.
			  	 	 $page['content'];
				}		
		} else if($p == 'years'){ //show years
	
		$sql = "SELECT name,game_year FROM media_games ORDER BY game_year DESC";
		$result = mysql_query($sql) or die(mysql_error());
		$exceptions = array('2007',''); //years we did not compete
			while($data = mysql_fetch_array($result)){
				$game_names['2007'] = '';
					$game_names[$data[1]] = $data[0];
				
			}

		 $folders = scandir($this->dir_photos);
			print_r($data);
		Arsort($folders);	//sort array by value descending order 
		
			echo 	'<div id="gal_games">'.
					'<div id="gal_games_inner">';
			foreach($folders as $folder){
		
				if($folder == '.' OR $folder == '..' OR $folder == 'load'){
					$forder = '';
				} else {
					echo '<div class="gal_thumbs">'.
					'<a href="?year='.$folder.'">'.$game_names[$folder].
					'<img src="http://combbat21.com/media/gallery/photos/thumb/'.$folder.'.jpg" alt="ThumbNail"/>'.
					$folder.'</a><br/>'.
					'</div>';		
				}
				
		 	}
			
			echo '</div></div>';
		
		} else if($p == 'albums'){ //show albums in input:year folder
			$folders = scandir($this->dir_photos.'/'.$y);

			echo '<div id="gal_overlay"><div id="photo_content"></div></div>';
			echo '<div id="gal_album">';
			foreach($folders as $albumFolder){
				
				if($albumFolder == '.' OR $albumFolder == '..'){
					$albumFolder = '';
				} else {
					
		$thumbnails = $this->randomThumbnail($this->dir_photos.$y.'/'.$albumFolder.'/');
		
					//'<a href="?year='.$y.'&album='.$albumFolder.'">'.$albumFolder.'</a>';
			
					echo ''. #TODO: remove style in img when randomthumbnail is clear
						 '<a class="gal_albums" href="?year='.$y.'&album='.$albumFolder.'">'.
				 		 '<img style="width: 130px;height:130px" src="'.$thumbnails.'" alt="THUMBNAIL"/>'.
						 '<span class="album_name">'.$albumFolder.'</span></a>';		
							
				}
		 	}
			
			echo '</div>';
		} else {
			$album_path = $this->dir_photos.$y.'/'.$album.'/';
			$normalPhotos = scandir($album_path);
/*
		$validPath = '/photos/2014/Building%20Season/test.jpg';
			$exif = exif_read_data($validPath, 'IFD0', TRUE);
			if(isset($exif) == true){
				if (@array_key_exists('DateTime', $exif)) {
					$strDate = $exif['DateTime'];
				
					@list( $idate, $itime ) = explode( ' ', trim($strDate) );
					@list( $iyear, $imonth, $iday ) = explode( ':', $date );
					$realDate = strtotime( "{$iyear}-{$imonth}-{i$day} {$itime}" );
					
					if(filemtime($normalPhotos) != $realDate){
						touch($normalPhotos,$realDate);
					}
				}
			}
								$picLink[$images.$file] = filemtime($normalPhotos); */
			###########################
			/*$page = (isset($_REQUEST['p']) ? $_REQUEST['p'] : null);  //get user p INPUT_ENV
			$currentpage = isset($page) ? (integer)$page : 1;   //get current page.. null = 1
			$totalImg = count($normalPhotos)-2; 				//scandir adds two items to array by default '.' and '..'
			$totalPages = ceil($totalImg / $this->imgPerPage);
			
			if (($currentpage > 0) && ($currentpage <= $totalPages)) { 
				$start = ($currentpage-1) * $numperpage; 
				for($i=$start;$i<=($numperpage+$start-1);$i++) { 
							
				}
			}*/
			######################
			
			echo '<div id="photosCont">';
			
			 foreach($normalPhotos as $photos){
			 	$loadedPhotos = $this->dir_cache.$y.'_'.$album.'_'.$photos; 
				#FORMAT: photos/load/2014_Building Season_name.jpeg
				$urlPhotos = $this->dir_photos.$y.'/'.$album.'/'.$photos;
				#FORMAT: photos/load/2014_building season_name.jpg 
			 	if($photos == '.' OR $photos == '..'){
					$photos = '';
				} else { 
						
					if(!file_exists($loadedPhotos)){
						$photoLink = 'image.php?y='.$y.'&a='.$album.'&i='.$photos;
					} else {
					 	$photoLink = $this->dir_cache.$y.'_'.$album.'_'.$photos;	
					}
				echo '<div class="photosBlock">'.	
				'<a href="'.$urlPhotos.'" target="_blank"><img src="'.$photoLink.'" alt="thumbnail"/></a><br/>'.
				'<span class="photoDate">'.$photos.'</span></div>';
				}
			 }//foreach
			 echo '</div>';
	
		}
		
	}//end of function
			
}//end of class


?>