<!DOCTYPE HTML>
<style type="text/css">
#four { background-image: none; }
#five { background-image: none ! important; }
</style>
<input type="text" value="Themed">
<input type="text" value="Not Themed" style="background-image: none">
<input type="text" value="Not Themed" style="background-image: none ! important">
<input type="text" value="Not Themed" id="four">
<input type="text" value="Not Themed" id="five">