SOURCE

<p class="p_0">background-position：默认为 图片原大小</p>
<p class="p_1">background-position：top center</p>
<p class="p_2">background-position：10px 20px</p>
<p class="p_3">background-position：10% 20%</p>

p{
    margin-top: 10px;
    padding: 10px;
    border: 10px solid rgba(10,10,10,.2);
    background-color: yellowgreen;
    background-image:url(https://www.w3school.com.cn/i/bg_flower.gif);
    background-repeat: no-repeat;
    background-size: contain;
}
.p_1{
    background-position: top center;
}
.p_2{
    background-position: 10px 20px;
}
.p_3{
    background-position: 10% 20%;
}