css class makes html element disappear

I have an html element which is an image . There is no problem seeing the image in mobile, but when you look at the page in computer, the image disappears. I found out the reason this element disappears is when I give it a class="ad_img". there is no style for appearing and disappearing this element inside that class. When I remove class="ad_img" the image shows up.

.ad_img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.ad_main_div {
  width: 100%;
  max-width: 800px;
}

.ad_main_panel {
  background-color: rgba(0, 0, 0, 0.00);
  border-radius: 3px;
  overflow: hidden;
  border: 3px solid rgba(0, 0, 0, 0.00);
  display: inline-block !important;
  position: relative;
  object-fit: cover;
  margin-top: 5px;
  margin-bottom: 5px;
  margin-right: auto;
  margin-left: auto;
  left: 0px;
  right: 0px;
  min-width: 100%;
  max-width: 800px;
  padding-bottom: 12.5%;
}

<center>
  <div class="ad_main_div">
    <p> With class </p>
    <button id="ad_main_button" class="ad_main_panel">
          <img src="https://pearlcapital.com/wp-content/uploads/2018/04/FB-Phone-GIF.gif"   id="ad_main_img" alt="No Image" class="ad_img"/>                 
    </button>
    
    <p> Without class </p> 
     <button id="ad_main_button" class="ad_main_panel">
          <img src="https://pearlcapital.com/wp-content/uploads/2018/04/FB-Phone-GIF.gif" id="ad_main_img" alt="No Image" />                 
     </button>
  </div>
</center>