Image inside a button only shown in half in emulator

It’s working fine in browser. But in my emulator (also in device. The top button should be in full circle actually):

My html:

<div class="float-bottom">
  <button class="button button-clear button-block" ng-click="camera()">
    <img class="bottom-button" src="img/camera-button.png" alt="">
  <div class="spacer" style="height: 10px;"></div>
  <button class="button button-clear button-block" ng-click="gallery()">
     <img class="bottom-button" src="img/gallery-button.png" alt="">


.float-bottom {
  position: absolute;
  bottom: 0px; width: 100%;
  z-index: 2147483647;

img.bottom-button {
   height: auto;

Any idea?