.container {
   width:100%;
   min-height:80vh;
   margin:auto;

   display: flex;
   align-items: center;
   justify-content: center; /* not really needed with auto margin on img*/
}
.container img {
   display: block;
   width: 80%;
   min-width:100px;
   max-width: 237px; /*actual image width*/
   height: auto; /* maintain aspect ratio*/
   margin: auto; /*optional centering of image*/
}