Add a value for the dimensions of xlarge app icons.

    <dimen name="thumbnail_width">160dp</dimen>

    <!-- The height that is used when creating thumbnails of applications. -->

    <dimen name="thumbnail_height">100dp</dimen>

    <!-- The standard size (both width and height) of an application icon that

         will be displayed in the app launcher and elsewhere. -->

    <dimen name="app_icon_size">64dip</dimen>

</resources>