Server load time can be high due to gigantic size of image files. When data is being fetched from server to the recipent, files with huge size take significant amount of time to get downloaded which increase the page load time.
Images often account for most of the downloaded bytes on a web page and also often occupy a significant amount of visual space. As a result, optimizing images can often yield some of the largest byte savings and performance improvements for your website: the fewer bytes the browser has to download, the less competition there is for the client’s bandwidth and the faster the browser can download and render useful content on the screen.
We will use several lossy compression techniques can be used to reduce the file size of your PNG and JPG files. By selectively decreasing the number of colors in the image, fewer bytes are required to store the data. The effect is nearly invisible but it makes a very large difference in file size, decreasing the page load time.