Change the [<< Prev] [Next >>] on listing to button image

[Makoshark]

This is something I have been wanting to do for some time. I would like to change the page navigation [<< Prev] 1 2 3 4 [Next >>] to button images like this
I found this in the /includes /languages/my template/english.php

  define('PREVNEXT_TITLE_FIRST_PAGE', 'First Page');
  define('PREVNEXT_TITLE_PREVIOUS_PAGE', 'Previous Page');
  define('PREVNEXT_TITLE_NEXT_PAGE', 'Next Page');
  define('PREVNEXT_TITLE_LAST_PAGE', 'Last Page');
  define('PREVNEXT_TITLE_PAGE_NO', 'Page %d');
  define('PREVNEXT_TITLE_PREV_SET_OF_NO_PAGE', 'Previous Set of %d Pages');
  define('PREVNEXT_TITLE_NEXT_SET_OF_NO_PAGE', 'Next Set of %d Pages');
  define('PREVNEXT_BUTTON_FIRST', '<<FIRST');
  define('PREVNEXT_BUTTON_PREV', '[<< Prev]');
  define('PREVNEXT_BUTTON_NEXT', '[Next >>]');
  define('PREVNEXT_BUTTON_LAST', 'LAST>>'); 

this seams to be what generates the prev next text. How do I get the define to display an image and keep the page numbers. Also how do you give the image mouse over description. I think this would make a great post. Thanks for any help, James