How to make a customized Nav-bar button icon

Hi, I’m trying to make a button to the right side of the nav-bar that is using my customized “cart.png” file in the img folder, how do I accomplish this?
Heres my navbar html:

<ion-nav-bar class="bar-balanced">
      <ion-nav-back-button >

      <ion-nav-buttons side="left">
      <button class="button button-icon button-clear ion-navicon" ng-click="login()">

    <<ion-nav-buttons side="right">
    <button class="button button-icon button-clear ion-gear-a" ng-click="goToCart()">


So I want to replace the with some kind of button that behaves like src=“img/cart.png” but I cant seem to make it work. How would I do this?