Define Image sprites with context to CSS ?

When a set of images is collaborated into one image, it is known as ‘Image Sprites’. As the loading every image on a webpage consumes time, using image sprites lessens the time taken and gives information quickly.
CSS coding:
img.add { width: 60px; height: 55px; background: url (image.god) 0 0; }
In this case, only the part needed is used. The user can save substantial margin and time through this.