Is your website not adaptable to mobile devices yet? Well, what are you waiting for? Having an entirely responsive website should be the first step in your mobile marketing strategy, guaranteeing your visitors a great user experience from any device. As well as a well adapted design, you should also keep your loading times in check: studies show that users tend to abandon websites that take longer than 4 seconds to load on their smartphones.
Another reason is that if you're using an image as a link, the alt text for that image will be treated similarly to the anchor text of a text link. However, we don't recommend using too many images for links in your site's navigation when text links could serve the same purpose. Lastly, optimizing your image filenames and alt text makes it easier for image search projects like Google Image Search to better understand your images.