Submit Button Image

I want to use a Submit Button Image instead of the standard Button. I searched on Google and SO and got a few different ways.

Which is the right way of using an Image as a Submit Button ?

Also i would want to add three states for the button - normal, hover, onclick

What i tried

HTML

<input type="submit" value="Subscribe">

CSS

input[type=submit] {
    background:url(../images/btn-subscribe.gif) none;
    text-indent:-9999px;
    width:109px;
    height:41px;
}

What shows up

enter image description here

What it should Display

enter image description here