need help to avoid shrinking of actual image while setting has a linearlarlayout backaground

Question

friend's i have to set an image has background for an linear layout,the background has been set well,but here the problem is the image has been shrinked its appearance. here my xml code

<?xml version="1.0" encoding="utf-8"?>
 <LinearLayout  xmlns:android="http://schemas.android.com/apk/res/android" 
 android:background="@drawable/directory_bg_new"
    android:orientation="vertical" android:gravity="fill_vertical"    
    android:layout_width="fill_parent" android:layout_height="fill_parent">
 <GridView xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@+id/myGrid" android:layout_width="fill_parent"
  android:layout_height="wrap_content" android:padding="10dp"
  android:verticalSpacing="10dp" android:horizontalSpacing="10dp"
  android:numColumns="4" android:columnWidth="60dp" android:stretchMode="columnWidth"
  android:tag="@string/temp" android:gravity="center"
  android:listSelector="@drawable/corner_orange" android:layout_weight="1.0" />
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:paddingTop="8dip" android:id="@+id/poweredby"
  android:layout_gravity="center_horizontal" android:layout_width="wrap_content"
  android:layout_height="wrap_content">
  <ImageView android:id="@+id/poweredby1" android:src="@drawable/power"
   android:layout_width="wrap_content" android:layout_height="15dp" />
  <ImageView android:id="@+id/poweredby2" android:src="@drawable/i_icon"
   android:layout_width="wrap_content" android:layout_height="wrap_content"
   android:layout_toRightOf="@+id/poweredby1" />
 </RelativeLayout>

</LinearLayout>

how can i avoid it,what attribute i need to add in the layout not to shrink the original image. thanks in advance.