明白了。

Android的工具，在你的用户主文件夹中创建一个.android文件夹。此文件夹包含在其中的每个虚拟设备单独的文件夹中存在的AVD文件夹。在每一个这种文件夹名为sdcard.img应该是present文件。此文件包含自动生成的SD卡内的影像为这个AVD。

The android tools create an .android folder in your users home folder. This folder contains an avd folder in which a separate folder for each virtual device exists. In each of this folders a file called sdcard.img should be present. This file contains the automatically created sd card image for this AVD.