Image is missing charts. How can I delay the image conversion a bit so that all charts get loaded.

[chdharm]

var urlToImage = require('url-to-image');
urlToImage('http://localhost:3000/', 'localhost.png').then(function() {
console.log("Completed !")
}).catch(function(err) {
console.error(err);
});

Is there a way in this library to delay image conversion after page load.
I am using charts which takes some time to load on page.