I currently have this, but it is not setting the background as expected:
<body style: background-image url()>
Also I need it to be a file not a link
Looks like @Sverre beat me to the suggestion of moving your CSS style to a separate file. If you prefer to leave it directly in the tags, you will have to reformat it a bit like so:
<body style="background-image: url('https://yourdomain.com/some-image.png')">