[SOLVED] Replace text

[peranha]

Can anyone help me to convert

to an image such as this website does on the posts?  I input the code into my database, and would like to get the image when looking at posts, or do I have to insert img code into the database.

[trq]

<?php

  $s = "hello:)";
  echo str_replace('','<img src="smillie.jpg">',$s);

?>

[cooldude832]

better idea is

<?php
$smiles = array("","")
$replacements = array("<img src=\"smiley.jpg\" />","<img src=\"sad.jpg\" />");
$string = " Happy  Sad";
$string = str_replace($smiles,$replacements,$string);
echo $string;

[peranha]

Thanks, The array is what I was looking for.