How to apply background Image on ScrollView android

I am apply background image on Relativelayout Under ScrollView. Image Appear on XML View but Not Appear on Actual device.

I have added ImageView on Ralativelayout

1.     >
   
       <RelativeLayout xmlns:android="http://ift.tt/nIICcg"
           android:layout_width="match_parent" android:layout_height="match_parent"
   
           android:id="@+id/parentView"
           >
    <ImageView
               android:layout_width="fill_parent"
               android:layout_height="fill_parent"
               android:src="@drawable/cloudbg"
               />
   
           <LinearLayout
               android:layout_width="match_parent"
               android:orientation="horizontal"
               android:id="@+id/vo"
               android:layout_below="@id/relativeLayout"
               android:layout_marginTop="20dp"
               android:layout_marginLeft="20dp"
               android:layout_height="wrap_content">
   
               <TextView
                   android:layout_width="100dp"
                   android:layout_height="wrap_content"
                   android:text="XYZ"
                   />
   
               <TextView
                   android:layout_width="wrap_content"
                   android:layout_marginLeft="25dp"
                   android:layout_height="wrap_content"
                   android:id="@+id/textvo"
                   android:text="Voter Number"
                   />
   
           </LinearLayout>
   
   
          </RelativeLayout>
   </ScrollView>
   
   

Thanks