Input [type = "image"] will not budge

I tried to flatten the marker, padding, top, to be at the same level as the other input and label, but it will not budge.

html code: see image

   input[type="image"] .button-update-cart{
top:100px;
}

In the form the image is not in place, for example: see this image

EDIT

.page-cart .cart-totals .promo-code .field .button-update-cart{
position:relative;
}

.page-cart .cart-totals .promo-code .field input[type="image"]
{
top:100px;

}

he does not work: (

Any insight would be appreciated!