There are many ways to represent a form submit button.
Using an img element wrapped around an href
<form id="testForm">
  <a href="javascript:document.getElementById['testForm'].submit()">
    <img src="button.gif"/>
  </a>
</form>
This is generally a messy and long-winded way.
Using input element with type="image"
<form>
  <input type="image" src="button.gif"/>
</form>
Slightly better, but the image isn’t an input and doesn’t really reflect its function!
Using button
<form>
  <button type="submit">
    <img src="button.gif" />
  </button>
</form>
Much better, the tag name used now reflects its function. You can also insert other inline and block level objects,
except for a and other form objects. Please see the links below for more details.
To make the button a reset button, simply change the type attribute to reset
To make the button trigger a JavaScript action, simply change the type attribute to button and add an
onclick attribute