Image optimization helps in improving page load speed, boosts websites' SEO ranking, and improves user experience. Page load speed is the amount of time taken by a web page to load completely. The websites having less than 2 seconds load speed are most loved by its users.
Image optimization is done by defining the images with the help of proper alt text to help Google spiders read through your images and rank them in search results.
Image optimization is delivering images with smallest possible size while maintaining the quality of the image. In image optimization we use alt tag to read text of image.