Answers for "z index in position fixed"

css z index

img {
  position: absolute; 
  /*position: relative;
  //position: fixed;*/
  left: 0px;
  top: 0px;
  z-index: -1;
}

The z-index property specifies the stack order of an element.

z-index on position absolute

#relative {
	position: relative;
	width: 40px;
	height: 100px;
	background: #000;
	z-index: 1;
	margin-top: 30px;
}
.absolute {
	position: absolute;
	top: 0; left: 0;
	width: 200px;
	height: 50px;
	background: yellow;
}