Simple Menu Background Image

Hello, I am trying to get a menu up within one of my wordpress pages, in the html itself. You can see it here:

https://digitalfilmacademy.com/wordpress/about

For some reason though, I cannot seem to get the background image that is behind the menu buttons to work. My css reads like this:

#navmenu ul {
margin: 0; padding: 0;
list-style-type: none; list-style-image: none;
}

#navmenu li {
display: inline;
}

#navmenu ul li a
{text-decoration:none; margin: 4px;
padding: 5px 20px 5px 20px; color: blue;
background-image:url(‘images/abt.jpg’)
}

#navmenu ul li a:hover {
color: purple;
background-image:url(‘images/abt.jpg’);
}

I have also tried a direct path to the images with the full url but this does not work either. Is there something wrong with my css? It seems pretty basic.