Change PayPal Button Image

<form target="paypal" action="https://www.paypal.com/cgi-bin/webscr" method="post">
 <input type="hidden" name="business" value="amit@alchemistsoftwares.com"/>
 <input type="hidden" name="cmd" value="_cart"/>
 <input type="hidden" name="add" value="7"/>
 <input type="hidden" name="item_name" value="Kodak A4 Threaded Flatbed"/>
 <input type="hidden" name="amount" value="70"/>
 <input type="hidden" name="currency_code" value="USD"/>
 <input type="image" name="submit" border="0" src="https://www.paypal.com/en_US/i/btn/btn_cart_LG.gif"  alt="PayPal - The safer, easier way to pay online"/>
 <img alt="" border="0" width="1" height="1"  src="https://www.paypal.com/en_US/i/scr/pixel.gif" />
</form>