resize the image of button background relative to screen resolution in HTML with CSS

I have a button with a image as a background and I would like to resize the image size depending on screen resolution. For the images, I use width:100%, but in this case, if I use it for the button, the button size adjust to the screen resolution, but not the image it uses as a background. What can I do so the image resize the same way as the button?

<!DOCTYPE html>
<html>
<body>
  <button class="dog"><img src="pictures/dog.png" ></button>
  <style>
  .dog {
    position:absolute;
    width:100%;
    left:1%;
    top:6%;
  }
</style>
</body>
</html>

Solution

You can remove the image inside your <button> element and set the image as a background to your button instead. Use CSS background properties like background-size to make the background automatically fit your button.

.bill {
  width: 180px;
  height: 80px;
  background: url("https://www.fillmurray.com/640/360");
  background-position: center;
  background-size: cover;
  color: floralwhite;
  font-weight: bold;
  font-size: 1.4em;
}

<button class="bill">Bill Me!</button>