React - component state not being set

Why is the output of the piece of code below "true"?

class InstagramGallery extends React.Component {

    constructor(props) {
        super(props);

        this.state = {
            images: true
        };
    }

    componentDidMount() {
        var accessToken = '*Instagram token*';
        var instagramApi = new Instagram(accessToken);
        instagramApi.userSelfMedia().then(function(result) {
            this.setState({
                images: false,
            });
        }, function(err) {
            console.log(err);
        });

    }

    render() {
        console.log(this.state.images); 
        return (
            <div className="instagram-gallery">

            </div>
        )
    }
}

From what I know, constructor is being called first. Therefore images=true, after that it renders with console.log(true), and componentDidMount is called. After data from instagram is fetched, and I update component state which should re-render the component with images=false. Where am I wrong?