CODE EXAMPLE FOR CSS

css transition on click

.crossRotate {
    outline: 0;
    /* other styles... */
}

.crossRotate:focus {
  -webkit-transform: rotate(45deg);
  -ms-transform: rotate(45deg);
  transform: rotate(45deg);
}

<img class="crossRotate" src="http://placehold.it/100" tabindex="1" />