Scale the image using START.

Scale the image using END.

Official Docs

FitStart

This will fit to the smallest size of the container, and it will align it to the start.

<ImageView android:layout_width="200dp"
           android:layout_height="200dp"
           android:src="@mipmap/ic_launcher"
           android:id="@+id/imageView"
           android:scaleType="fitStart"
           android:layout_gravity="center"
           android:background="@android:color/holo_orange_light"/>

http://i.stack.imgur.com/a5bmE.png

http://i.stack.imgur.com/OfVmD.png

FitEnd

This will fit to the smallest size of the container, and it will align it to the end.

<ImageView android:layout_width="200dp"
           android:layout_height="100dp"
           android:src="@mipmap/ic_launcher"
           android:id="@+id/imageView"
           android:scaleType="fitEnd"
           android:layout_gravity="center"
           android:background="@android:color/holo_orange_light"/>

http://i.stack.imgur.com/NwOJG.png

http://i.stack.imgur.com/CuXz3.png