How do I load images asynchronously in a website?

Whenever browser encounters <img> tag it loads the associated image from specified src asynchronously. Each image tag is separate asych request to server. So you look at following, You will see others resource are loading parallel with image. So dont worry about them -)

As the other answers have mentioned, this is the default behaviour. However, maybe your question intent was different. I suspect you want to do stuff in JavaScript before loading images for some reason. In which case you can do that using JavaScript. You can create an image like so: var mySuperImage = new Image(); mySuperImage.src = "images/mySuperImage.png"; document.getElementById("my-super-image-container").appendChild(mySuperImage); Note that depending on what you are doing (a website, a single page application, a game) this can have a negative impact on your SEO.If that is indeed something you need but don't want to have the images url specified in the JavaScript file (which is very noble), you could use data attributes and a script to have the same result. Something like: [...] <div data-imageurl="images/mySuperImage.png"></div> [...] document.querySelector("div[data-imageurl]").forEach(function(imageContainer){ var image = new Image(); image.src = imageContainer.dataset.imageurl; imageContainer.appendChild(image); }); In this code with use data-something attributes which allow you to specify custom data for your element to define all your "asynchronous" images. Then, when you are ready (after a JavaScript process or something), you can launch the script that will create an image inside every div that has the attribute data-imageurl.Note that if you do that on page load without the "appendChild" page, you can load your images in the background so it's faster when you add it to the page to appear.Is all that a good idea? Probably not, but you never know what kind of weird use case one could have.

No special handling is usually required, but if you provide width and height inside the img tag, the browser will use the information for a faster rendering of the page.