Código HTML:
<script language="javascript">
function abrir(pid){
getElementByID(pid).style.display="block";
}
</script>
<table border="0">
<tr>
<td><div align="center"><a href="javascript:abrir(1)"><img src="img/img/1.jpg" width="88" height="50" /></a></div></td>
</tr>
<tr>
<td class="Estilo1"><div id="1" style="display:none" align="center">
<textarea name="textfield" cols="50" rows="5" id="textfield"></textarea>
</div></td>
</tr>
</table>