How does CSS render a sprite?

Question

css

By creating an offset to the side by half, the neighboring image became noticeable, that is, that in fact the entire sprite is placed under the "mask" every time you place an image element and not just its specified part?

#home {
    left: 0px;
    width: 46px;
    background: url('img_navsprites.gif') 0 0;
}

#prev {
    left: 63px;
    width: 43px;
    background: url('img_navsprites.gif') -25px 0;
}