how can we add an image as background ..and too should be equal to screen size

Answer 1

you need to use css for such styling. In css the property of background-image:url(); for setting a background image and background-size: cover/contain; to make it equal to the screen size. Adding these properties should do the job

Answer 2

css property:
background: url();
background-size: cover;

Answer 3

please reframe your question. is it when deigning a web page?