We recommend adding the CSS globally in the Site Settings > Integrations to use the CSS Class across multiple pages and for ease of update. You can place the .img-rotate on any image but if you would like a custom shape (i.e. square) you will need to wrap it in a group.
1. To make animation work, paste in ADVANCED SETTINGS > CUSTOM CSS:
.img-rotate {
  animation: spin 8s linear infinite;
  transform-origin: center;
  height: 100%;
  width: 100%;
  overflow: visible;
}

@keyframes spin {
  to { transform: rotate(-360deg); }
}
2. Applying the class:
.img-rotate ON the circle image
.img-rotate on the GROUP