<div>
<div style="margin: 5px;">
<div class="smallfont" style="margin-bottom: 1px;">
<input onclick="if (this.parentNode.parentNode.getElementsByTagName('div')[1].getElementsByTagName('div')[0].style.display != '') { this.parentNode.parentNode.getElementsByTagName('div')[1].getElementsByTagName('div')[0].style.display = ''; this.innerText = ''; this.value = 'HIDE'; } else { this.parentNode.parentNode.getElementsByTagName('div')[1].getElementsByTagName('div')[0].style.display = 'none'; this.innerText = ''; this.value = 'SHOW'; }" style="font-size: 14px; margin: 0px; padding: 0px; width: 250px;" type="button" value="SHOW" /></div>
<div class="alt2" style="border: 0px inset; margin: 0px; padding: 6px;">
<div style="display: none;">
<img border="0" height="320" src="http://1.bp.blogspot.com/-1s3MrS9MGM8/VgLdvKjrqLI/AAAAAAAAAVo/yUvV9fK-ikQ/s1600/naca.jpg" style="margin-left: 1em; margin-right: 1em;" /><img border="0" src="http://1.bp.blogspot.com/-1s3MrS9MGM8/VgLdvKjrqLI/AAAAAAAAAVo/yUvV9fK-ikQ/s400/naca.jpg" /></div>
</div>
</div>
</div>
</div>
contoh :
