Favicon and background won't show up

Hi everyone, I’ve got a problem and it’s super frustrating. I made a nice background for my site so I tried to add it to the site. So I went to dashboard > customize your site > background image and then clicked on Upload new. So I selected a file, and clicked open but nothing happened. Then after a bit of research I tried this: I uploaded the image to the /images folder in the themes folder and I edited style.css to this:
body {
background: url(images\bg.png) repeat-y center;
line-height: 1;
}

So I opened my FTP programme (FTPRush), deleted the old style.css and uploaded the new one. Refreshed my site, but the background is not there. What do I need to do to make it show up?

Also: my favicon won’t show up. I uploaded in the themes folder but it just won’t show.