style.css

/* Target the avatar container for user+bot */
.chatbot-message .avatar-container {
  width: 256px !important;
  height: 256px !important;
  min-width: 256px !important;
  min-height: 256px !important;
}

/* Make sure the image still fills the circle */
.chatbot-message .avatar-container img {
  width: 100% !important;
  height: 100% !important;
  object-fit: cover;
}