ci分页类，怎么把显示的数字（上页、下页、首页、末页）换成图片显示呢？

具体怎么改，请指点指点！！！<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');/** * CodeIgniter * * An open source application development framework for PHP 5.1.6 or newer * * @package		CodeIgniter * @author		ExpressionEngine Dev Team * @copyright	Copyright (c) 2008 - 2011, EllisLab, Inc. * @license		http://codeigniter.com/user_guide/license.html * @link		http://codeigniter.com * @since		Version 1.0 * @filesource */// ------------------------------------------------------------------------/** * Pagination Class * * @package		CodeIgniter * @subpackage	Libraries * @category	Pagination * @author		ExpressionEngine Dev Team * @link		http://codeigniter.com/user_guide/libraries/pagination.html */class CI_Pagination {	var $base_url			= ''; // The page we are linking to	var $prefix				= ''; // A custom prefix added to the path.	var $suffix				= ''; // A custom suffix added to the path.	var $total_rows			=  0; // Total number of items (database results)	var $per_page			= 10; // Max number of items you want shown per page	var $num_links			=  2; // Number of "digit" links to show before/after the currently viewed page	var $cur_page			=  0; // The current page being viewed	var $use_page_numbers	= FALSE; // Use page number for segment instead of offset	var $first_link			= '&lsaquo; First';	var $next_link			= '>';	var $prev_link			= '<';	var $last_link			= 'Last &rsaquo;';	var $uri_segment		= 3;	var $full_tag_open		= '';	var $full_tag_close		= '';	var $first_tag_open		= '';	var $first_tag_close	= ' ';	var $last_tag_open		= ' ';	var $last_tag_close		= '';	var $first_url			= ''; // Alternative URL for the First Page.	var $cur_tag_open		= ' <strong>';	var $cur_tag_close		= '</strong>';	var $next_tag_open		= ' ';	var $next_tag_close		= ' ';	var $prev_tag_open		= ' ';	var $prev_tag_close		= '';	var $num_tag_open		= ' ';	var $num_tag_close		= '';	var $page_query_string	= FALSE;	var $query_string_segment = 'per_page';	var $display_pages		= TRUE;	var $anchor_class		= '';	/**	 * Constructor	 *	 * @access	public	 * @param	array	initialization parameters	 */	public function __construct($params = array())	{		if (count($params) > 0)		{			$this->initialize($params);		}		if ($this->anchor_class != '')		{			$this->anchor_class = 'class="'.$this->anchor_class.'" ';		}		log_message('debug', "Pagination Class Initialized");	}	// --------------------------------------------------------------------	/**	 * Initialize Preferences	 *	 * @access	public	 * @param	array	initialization parameters	 * @return	void	 */	function initialize($params = array())	{		if (count($params) > 0)		{			foreach ($params as $key => $val)			{				if (isset($this->$key))				{					$this->$key = $val;				}			}		}	}	// --------------------------------------------------------------------	/**	 * Generate the pagination links	 *	 * @access	public	 * @return	string	 */	function create_links()	{		// If our item count or per-page total is zero there is no need to continue.		if ($this->total_rows == 0 OR $this->per_page == 0)		{			return '';		}		// Calculate the total number of pages		$num_pages = ceil($this->total_rows / $this->per_page);		// Is there only one page? Hm... nothing more to do here then.		if ($num_pages == 1)		{			return '';		}		// Set the base page index for starting page number		if ($this->use_page_numbers)		{			$base_page = 1;		}		else		{			$base_page = 0;		}		// Determine the current page number.		$CI =& get_instance();		if ($CI->config->item('enable_query_strings') === TRUE OR $this->page_query_string === TRUE)		{			if ($CI->input->get($this->query_string_segment) != $base_page)			{				$this->cur_page = $CI->input->get($this->query_string_segment);				// Prep the current page - no funny business!				$this->cur_page = (int) $this->cur_page;			}		}		else		{			if ($CI->uri->segment($this->uri_segment) != $base_page)			{				$this->cur_page = $CI->uri->segment($this->uri_segment);				// Prep the current page - no funny business!				$this->cur_page = (int) $this->cur_page;			}		}				// Set current page to 1 if using page numbers instead of offset		if ($this->use_page_numbers AND $this->cur_page == 0)		{			$this->cur_page = $base_page;		}		$this->num_links = (int)$this->num_links;		if ($this->num_links < 1)		{			show_error('Your number of links must be a positive number.');		}		if ( ! is_numeric($this->cur_page))		{			$this->cur_page = $base_page;		}		// Is the page number beyond the result range?		// If so we show the last page		if ($this->use_page_numbers)		{			if ($this->cur_page > $num_pages)			{				$this->cur_page = $num_pages;			}		}		else		{			if ($this->cur_page > $this->total_rows)			{				$this->cur_page = ($num_pages - 1) * $this->per_page;			}		}		$uri_page_number = $this->cur_page;				if ( ! $this->use_page_numbers)		{			$this->cur_page = floor(($this->cur_page/$this->per_page) + 1);		}		// Calculate the start and end numbers. These determine		// which number to start and end the digit links with		$start = (($this->cur_page - $this->num_links) > 0) ? $this->cur_page - ($this->num_links - 1) : 1;		$end   = (($this->cur_page + $this->num_links) < $num_pages) ? $this->cur_page + $this->num_links : $num_pages;		// Is pagination being used over GET or POST?  If get, add a per_page query		// string. If post, add a trailing slash to the base URL if needed		if ($CI->config->item('enable_query_strings') === TRUE OR $this->page_query_string === TRUE)		{			$this->base_url = rtrim($this->base_url).'&'.$this->query_string_segment.'=';		}		else		{			$this->base_url = rtrim($this->base_url, '/') .'/';		}		// And here we go...		$output = '';		// Render the "First" link		if  ($this->first_link !== FALSE AND $this->cur_page > ($this->num_links + 1))		{			$first_url = ($this->first_url == '') ? $this->base_url : $this->first_url;			$output .= $this->first_tag_open.'<a '.$this->anchor_class.'href="'.$first_url.'">'.$this->first_link.'</a>'.$this->first_tag_close;		}		// Render the "previous" link		if  ($this->prev_link !== FALSE AND $this->cur_page != 1)		{			if ($this->use_page_numbers)			{				$i = $uri_page_number - 1;			}			else			{				$i = $uri_page_number - $this->per_page;			}			if ($i == 0 && $this->first_url != '')			{				$output .= $this->prev_tag_open.'<a '.$this->anchor_class.'href="'.$this->first_url.'">'.$this->prev_link.'</a>'.$this->prev_tag_close;			}			else			{				$i = ($i == 0) ? '' : $this->prefix.$i.$this->suffix;				$output .= $this->prev_tag_open.'<a '.$this->anchor_class.'href="'.$this->base_url.$i.'">'.$this->prev_link.'</a>'.$this->prev_tag_close;			}		}		// Render the pages		if ($this->display_pages !== FALSE)		{			// Write the digit links			for ($loop = $start -1; $loop <= $end; $loop++)			{				if ($this->use_page_numbers)				{					$i = $loop;				}				else				{					$i = ($loop * $this->per_page) - $this->per_page;				}				if ($i >= $base_page)				{					if ($this->cur_page == $loop)					{						$output .= $this->cur_tag_open.$loop.$this->cur_tag_close; // Current page					}					else					{						$n = ($i == $base_page) ? '' : $i;						if ($n == '' && $this->first_url != '')						{							$output .= $this->num_tag_open.'<a '.$this->anchor_class.'href="'.$this->first_url.'">'.$loop.'</a>'.$this->num_tag_close;						}						else						{							$n = ($n == '') ? '' : $this->prefix.$n.$this->suffix;							$output .= $this->num_tag_open.'<a '.$this->anchor_class.'href="'.$this->base_url.$n.'">'.$loop.'</a>'.$this->num_tag_close;						}					}				}			}		}		// Render the "next" link		if ($this->next_link !== FALSE AND $this->cur_page < $num_pages)		{			if ($this->use_page_numbers)			{				$i = $this->cur_page + 1;			}			else			{				$i = ($this->cur_page * $this->per_page);			}			$output .= $this->next_tag_open.'<a '.$this->anchor_class.'href="'.$this->base_url.$this->prefix.$i.$this->suffix.'">'.$this->next_link.'</a>'.$this->next_tag_close;		}		// Render the "Last" link		if ($this->last_link !== FALSE AND ($this->cur_page + $this->num_links) < $num_pages)		{			if ($this->use_page_numbers)			{				$i = $num_pages;			}			else			{				$i = (($num_pages * $this->per_page) - $this->per_page);			}			$output .= $this->last_tag_open.'<a '.$this->anchor_class.'href="'.$this->base_url.$this->prefix.$i.$this->suffix.'">'.$this->last_link.'</a>'.$this->last_tag_close;		}		// Kill double slashes.  Note: Sometimes we can end up with a double slash		// in the penultimate link so we'll kill all double slashes.		$output = preg_replace("#([^:])//+#", "\\1/", $output);		// Add the wrapper HTML if exists		$output = $this->full_tag_open.$output.$this->full_tag_close;		return $output;	}}// END Pagination Class/* End of file Pagination.php *//* Location: ./system/libraries/Pagination.php */