Background image changes based on fluid size

Change of body CSS changes the sixe of image based on size of device/

body {
/* Location of the image */
background-image: url(images/IMG_7442.JPG);
/* Image is centered vertically and horizontally at all times */
background-position: center center;
/* Image doesn't repeat */
background-repeat: no-repeat;
/* Makes the image fixed in the viewport so that it doesn't move when
the content height is greater than the image height */
background-attachment: fixed;
/* This is what makes the background image rescale based on its container's size */
background-size: cover;
/* Pick a solid background color that will be displayed while the background image is loading */
background-color: #464646;}