.glow img:last-child {
    display: none;  
}
.glow:hover img:last-child {
    display: inline-block;  
  }
.glow:hover img:first-child {
    display: none;  
}

.glow2 img:last-child {
    display: none;  
}
.glow2:hover img:last-child {
    display: inline-block;  
  }
.glow2:hover img:first-child {
    display: none;  
}