For them, rear view mirrors are useful for adding perfect makeup retouches.

对于女士们来说，后视镜在补妆的时候用处更大一些。

When you work on more complicated retouches that might have dozens of layers, it makes it much quicker when you can see easily which layer is which.

当你处理有几十个层的图片时，这样做能一眼看出哪个层是哪个。