影像图层切得格式是webp类型，设置的背景色是白色，前端用代码直接处理容差变成透明色

const imageryProvider = new Cesium.SuperMapImageryProvider(
  {
    url:'iserver/services/url',name: `影像`,
  }
)
const layer = imageryLayers.addImageryProvider(imageryProvider, i) 
layer.show = config.show
layer.alpha = config.alpha
layer.transparentBackColor = Cesium.Color.fromCssColorString('#ffffff')
layer.transparentBackColorTolerance = 0.1w

文档参考：

ImageryLayer - Cesium Documentation

处理之后，白色背景变成透明色