html, body {
  margin: 0;
  padding: 0;
  height: 100%;
}

body {
  display: flex;
  flex-direction: column;
}

.center {
  flex: 1; 
  display: flex;
  align-items: center;     
  justify-content: center;  
}

a {
  display: contents;
}

.center img {

width:30%;
-webkit-user-drag: none;
user-drag: none;
-webkit-user-select: none;
-moz-user-select: none;
user-select: none;
}

footer img {

  width:5%;
  -webkit-user-drag: none;
  user-drag: none;
  -webkit-user-select: none;
  -moz-user-select: none;
  user-select: none;
  }

footer {
  text-align: center;
  padding: 10px;
}

@media (max-width: 600px) {
  .center img {
    width: 70%; /* of 100%, naar wens */
  }

  footer img {

    width:10%;

    }
  
}