my backgound image in css file isnt getting updated code example

Example 1: css background image is not show change default picture

$("html").css({ "background-image": "url('../images/pattern%20copy.png'), url('../images/visuals/visual3-edit.jpg')", "background-position": "center", "background-repeat": "no-repeat", "background-attachment": "fixed"  });

Example 2: background image in css is not working

background-image: url(nickcage.jpg); // first problem may be missing quotation mark
// Second may be wrong path 
// check the name of the file if there is any error
// check whether you are using proper extension of the file