在 Windows 8.1 设置里面设置头像，开机不显示头像。

检索了很多内容发现可能是 Windows 8.1 的特有的问题。最终，在 https://www.reddit.com/r/techsupport/comments/pc59oo/windows_81_account_photo_not_appearing_on_login 上找到了解决方法，即使用 Quick User Manager 设置头像。

然而，此软件 How to 写道：

Note: This feature may not work properly on Windows 8/8.1, because changing the user tile is only available for Microsoft accounts. Quick user manager successfully changes the user tile, but it is not displayed in the Start/Welcome screen. You don't have any option to set the user tile's picture in the User accounts control panel applet either. Let's hope the new Windows 10 will remove this limitation.

所以，暂不清楚是否是巧合导致问题解决……