The media-type attribute for subfolders is left empty, such as that for the pictures folder, which is empty in my example, but normally contains the graphic source files for any embedded pictures.

用于子文件夹的media - type属性是空的(例如我示例中的Pictures文件夹)，但通常会在这些子文件夹中包含任何嵌入图形的图形源文件。

youdao