.front-page article header h2 {
display :none;
}



.index article h2 {
display :none;
}



.parent {
   width: 300px; /* I took the width from your post and placed it in css */
   height: 43px;
}

/* This will style any  element in .parent div */
.parent img {
  display: block;
  margin-left: auto;
  margin-right: auto; 
  height: 40%;
   width: 40%;
 
  
}