changing bullet style in footer

Hello
I am using the twenty ten theme and have set up a child theme, I currently have square bullets in my footer list, but I want to change to an arrow bullet I have created as a gif. I have added the following code into my css but I still get square bullets, please could you advise what I am doing wrong with the css?

}
#footer li {
list-style: image-http://www.kidsmoderndesign.co.uk/wp-content/uploads/2012/02/arrow.gif;
color: #000000;
.widget-title,
.wp-caption-text {
font-family: “Helvetica Neue”, Helvetica;
}

Many thanks