/* 5列画像（上書き）*/
.img-thumbnail251 {
  margin:0.3rem;
  padding: 0rem;
  border: 1px solid gray;
  border-radius: 0.15rem;
  transition: all .2s ease-in-out;
  display: inline-block;
  max-width: 18%;
  height: auto;
  box-shadow: 0 2px 5px 0 rgba(0, 0, 0, 0.16), 0 2px 10px 0 rgba(0, 0, 0, 0.12); 
}

@media (min-width:544px) and (max-width:768px) {
 .img-thumbnail251 {
  max-width: 22%;
  }
  }

@media (max-width:543px) {
 .img-thumbnail251 {
  max-width: 20%;
  }
}