.anniu{
background-image:url(images/y.gif);
font-size:0px;
color:#FFFFFF;
cursor:pointer;
width:150px;
height:70px;
border:0px;
}
background-image:url(images/y.gif);
font-size:0px;
color:#FFFFFF;
cursor:pointer;
width:150px;
height:70px;
border:0px;
}
<input type="submit" name="Submit" value="提交" class="anniu"/>