EditText keyboard modifies Layout

Good morning everyone!
I'm working on a game for Android, which has a EditText numeric type. By touching it, the keyboard is displayed, and in doing so, it modifies the size of my layout parent, which is a RelativeLayout . The problem is that it is assigned to the property android:background an image .png and this is scaled to the size of RelativeLayout and does not look good.
Is there any way this does not happen?

I add the .xml as a guide, although it's a bit long:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/juego"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    tools:context="derivadadx.juegodelnumero.Juego"
    android:background="@drawable/fondo">

    <EditText
        android:id="@+id/numInput"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="@dimen/margin"
        android:ems="10"
        android:inputType="number"
        android:hint="@string/numInput"
        android:textColorHint="@color/negro"
        android:gravity="center"
        android:background="@drawable/borde_rojo"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:imeOptions="actionDone"/>

    <Button
        android:id="@+id/verificar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_below="@id/numInput"
        android:layout_marginTop="@dimen/separacion_elementos"
        android:text="@string/verificar"
        android:background="@drawable/boton_negro"/>

    <LinearLayout
        android:id="@+id/columnas"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_below="@id/verificar"
        android:layout_marginTop="@dimen/separacion_elementos"
        android:background="@drawable/borde_verde">

        <TextView
            style="@style/AreaDeResultados"
            android:text="@string/columna_numero"/>

        <TextView
            style="@style/AreaDeResultados"
            android:text="@string/columna_aciertos"/>

        <TextView
            style="@style/AreaDeResultados"
            android:text="@string/columna_regular"/>
    </LinearLayout>

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@+id/columnas"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="2dp"
        android:background="@drawable/borde_azul">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/numeros"
                style="@style/AreaDeResultados"/>

            <TextView
                android:id="@+id/aciertos"
                style="@style/AreaDeResultados"/>

            <TextView
                android:id="@+id/regulares"
                style="@style/AreaDeResultados"/>
        </LinearLayout>
    </ScrollView>
</RelativeLayout>

What makes this show:

And when you hit the EditText field, this is what happens:

There you can see how he modifies the ScrollView and other elements within the RelativeLayout , which is not the problem, but modifies the image of background of it.