1、同时使用背景色、背景图片

参考链接：链接

以下样式，背景色在图片下方(缺点：图片不透明时，背景色会被完全遮挡。)

.header {
	height: 100%;
	width: 100%;
	background-color: #000;
	background-image: url('/static/images/back.png') ;
	background-repeat: no-repeat;
	background-size: 100% 100%;
}

2、两张图片叠加

参考链接：链接

<view class="header">
	<view class="header-box"></view>
</view>

.header {
	height: 100%;
	width: 100%;
	background-image: url('/static/images/back.png') ;
	background-repeat: no-repeat;
	background-size: 100% 100%;
	position: relative;
	.header-box{
		position: absolute;
		top: 0;
		bottom: 0;
        left:0;
        right:0;
		background: url('/static/images/back1.png') ;
		background-repeat: no-repeat;
		background-size: 100% 100%;
		mix-blend-mode: overlay;
	}
}

底图： 

遮罩图 ：

合成图： 

3、多张图片平铺

参考链接：链接

原图：

横向平铺：

.header {
	height: 80vh;
	width: 100%;
	background: url('/static/images/index_after.png') center left no-repeat,
		url('/static/images/index_after.png') center right no-repeat,
		url('/static/images/index.png') center left repeat-x;
}

纵向平铺：

.header {
	height: 80vh;
	width: 100%;
	background: url('/static/images/index_after.png') center top no-repeat,
	    url('/static/images/index_after.png') center bottom no-repeat,
		url('/static/images/index.png') center top repeat-y;
}