#gallery img{
  height:100px;
  border-radius:20px;
  margin:10px;
  box-shadow:2px 2px 2px black;
}
html, body {
  height: 100%;
  margin: 0;
}
#slideshow{
  min-height: 100%; 
  background-color:cyan;
}
#slideshow img{
  width:100%;
}