Low (ldpi): 120dpi
Medium (mdpi): 160dpi
High (hdpi): 240dpi
Extra High (xhdpi): 320dpi (Added in API Level 8)
res/drawable-ldpi/icon.png (36x36 pixels)
res/drawable-mdpi/icon.png (48x48 pixels)
res/drawable-hdpi/icon.png (72x72 pixels)
res/drawable-xhdpi/icon.png (96x96 pixels, if supported)
res/drawable-ldpi/logo.png (150x150 pixels)
res/drawable-mdpi/logo.png (200x200 pixels)
res/drawable-hdpi/logo.png (300x300 pixels)