Would you like to create a button like the left button with an image?
You can do it with just HTML code without any javascript or so ever...Copy the code below..
<button type="button" name="login_button" class="button"><img src="images/lock.png" width="15" height="15" border="0" /> Login</button>
The button will look like this...
So, if you like to have a button just like mine, you got to have the css style for this button.
.button{background:url(images/button.png) no-repeat 0 0;width:80px;height:34px;border:none;color:#fff;cursor:pointer;text-align:center;line-height:34px;font-weight: bold;}
And now the last path is the image, save this image (below) in the location that your file can reach it.
 |  |
Hope you manage to do it...