CSS Image Sprites
An image sprite is a sum of images placed in a single image.
CSS Sprite is an important CSS feature that allows you to save space and time by gathering together the images that are summoned to the site and making them into a single file. This will reduce the opening speed of your site, which will be useful to you for SEO
First of all, we create a transparent image file with a Photoshop. We save this file as PNG format that we use on our website and appear on every page. It is used for a picture of your theme that is repeated on every page of your website.