Performance is a crucial factor when building websites. Whenever we load a web page, the browser sends a request to each and every file that is linked in the HTML and CSS files. Designers use CSS image sprites to reduce the number of requests to the server. Using data URIs is also another good alternative to reduce server requests.
Data URI represents a file type and it’s content in an text string which is encoded using the base64 encoding system. The beauty of this string is that you can directly store an image in the HTML or CSS file itself, rather than referring to the external source.