is there a way to make the image show up the same way in all resolutions so that it looks the same on any computer?
You can never get it exactly the same, but you can make it stretch to fit almost any dimension monitor by adding this to your child theme style sheet:
body {
/* stretches background image */
-o-background-size: 100%, auto;
-moz-background-size: 100%, auto;
-webkit-background-size: 100%, auto;
background-size: 100%, auto;
}
That probably doesn’t work in MSIE, but perhaps it does. I don’t bother testing in MSIE as I am tired of jumping through hoops to support it.