Answers for "html auto background image in html"

background image size css

#example1 {
  background: url(mountain.jpg);
  background-repeat: no-repeat;
  background-size: auto;
}

#example2 {
  background: url(mountain.jpg);
  background-repeat: no-repeat;
  background-size: 300px 100px;
}

how to change background image in html

<style>
div {
  background-image: url('img_girl.jpg');
}
</style>