<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
       >

        <ImageView
            android:id="@+id/imageView1"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:src="@drawable/bergsteiger2"
            android:layout_alignParentTop="true"
            android:adjustViewBounds="true"
            android:layout_above="@+id/start" />

         <ImageButton
            android:id="@+id/start"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"

            android:layout_above="@+id/uebungen"
            android:background="?android:selectableItemBackground"

            android:src="@drawable/start"
            />

    <ImageButton
            android:id="@+id/anleitung"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_toRightOf="@+id/uebungen"
            android:layout_above="@+id/impressum"
            android:background="?android:selectableItemBackground"

            android:src="@drawable/anleitung"
            />
    <ImageButton
            android:id="@+id/uebungen"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"


            android:background="?android:selectableItemBackground"
            android:layout_above="@+id/impressum"
            android:src="@drawable/uebungen"
            />



         <ImageButton
            android:id="@+id/impressum"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"


            android:background="?android:selectableItemBackground"
            android:layout_alignParentBottom="true"
                    android:layout_centerHorizontal="true"
            android:src="@drawable/impressum"
            />

    </RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_above="@+id/start"
        android:layout_alignParentTop="true"
        android:adjustViewBounds="true"
        android:src="@drawable/bergsteiger2" />

    <RelativeLayout
        android:id="@+id/relativeLayout1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_above="@+id/impressum"
        android:orientation="horizontal"


        android:layout_centerHorizontal="true"
        android:adjustViewBounds="true" >

        <ImageButton
            android:id="@+id/anleitung"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_toRightOf="@+id/uebungen"
            android:background="?android:selectableItemBackground"
            android:src="@drawable/anleitung" />

        <ImageButton
            android:id="@+id/uebungen"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"

            android:adjustViewBounds="true"
            android:background="?android:selectableItemBackground"
            android:scaleType="fitXY"
            android:src="@drawable/uebungen" />
    </RelativeLayout>

    <ImageButton
        android:id="@+id/impressum"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:adjustViewBounds="true"
        android:background="?android:selectableItemBackground"
        android:scaleType="fitXY"
        android:src="@drawable/impressum" />

    <ImageButton
        android:id="@+id/start"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_above="@+id/relativeLayout1"
        android:layout_alignParentLeft="true"
        android:adjustViewBounds="true"
        android:background="?android:selectableItemBackground"
        android:scaleType="fitXY"
        android:src="@drawable/start" />

</RelativeLayout>

<LinearLayout
        android:id="@+id/relativeLayout1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_above="@+id/impressum"
        android:orientation="horizontal"
        android:layout_centerHorizontal="true"
        android:adjustViewBounds="true"
        android:weightSum="2">

        <ImageButton
            android:id="@+id/anleitung"
            android:layout_width="0dp"
            android:layout_weigth="1"
            android:layout_height="wrap_content"
            android:layout_toRightOf="@+id/uebungen"
            android:background="?android:selectableItemBackground"
            android:src="@drawable/anleitung" />

        <ImageButton
            android:id="@+id/uebungen"
            android:layout_width="0dp"
            android:layout_weigth="1"
            android:layout_height="wrap_content"
            android:adjustViewBounds="true"
            android:background="?android:selectableItemBackground"
            android:scaleType="fitXY"
            android:src="@drawable/uebungen" />
    </LinearLayout>