(1)drawable-hdpi里面存放高分辨率的图片,如WVGA (480x800),FWVGA (480x854)(2)drawable-mdpi里面存放中等分辨率的图片,如HVGA (320x480)(3)drawable-ldpi里面存放低分辨率的图片,如QVGA (240x320)
