Adding image to nav button or in between nav buttons

Hello,
I would like to add a small image in between or to the background of the words/buttons on my navigation bar.
https://www.studyathomemama.ca

I’ve tried the following code with no luck:
#nav > div > ul > li {
background: url(“https://studyathomemama.ca/?attachment_id=747”) no-repeat scroll right 14px transparent;
padding-right: 40px;
}

Thanks for any help!