Here is source code of the Program to Change the Image Displayed on the Screen in Android. The program is successfully compiled and run on a Windows system using Eclipse Ide. The program output is also shown below.
Note
Remember to put your images in res/drawable-hdpi/ directory and then clean your project in order to use the images in your current working Application.

Main Activity


package com.example.changeiamge;

import android.app.Activity;
import android.graphics.Typeface;
import android.os.Bundle;
import android.renderscript.Type;
import android.view.Gravity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.RadioGroup;
import android.widget.RadioGroup.OnCheckedChangeListener;
import android.widget.TextView;

public class MainActivity extends Activity implements OnCheckedChangeListener {

RadioGroup group1, group2;
Button gen;
ImageView img;

@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

group1 = (RadioGroup) findViewById(R.id.rg1);
group1.setOnCheckedChangeListener((OnCheckedChangeListener) this);

group2 = (RadioGroup) findViewById(R.id.rg2);
group2.setOnCheckedChangeListener((OnCheckedChangeListener) this);

img = (ImageView) findViewById(R.id.imageView1);
// oncheckedChanged function
gen = (Button) findViewById(R.id.button1);
gen.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub

}
});

}

@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
// TODO Auto-generated method stub
switch (checkedId) {
case R.id.radioButton1:
img.setImageResource(R.drawable.image4);
break;

case R.id.radioButton2:
img.setImageResource(R.drawable.image5);
break;

case R.id.radioButton3:
img.setImageResource(R.drawable.image6);
break;

case R.id.radioButton4:
img.setImageResource(R.drawable.image7);
break;

default:
break;
}
}
}

ActivityMain.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:paddingBottom="40px"
android:weightSum="2" >

<RadioGroup
android:id="@+id/rg1"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="vertical" >

<RadioButton
android:id="@+id/radioButton1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:layout_marginTop="20dp"
android:text="Image2" />

<RadioButton
android:id="@+id/radioButton2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/radioButton1"
android:layout_alignBottom="@+id/radioButton1"
android:layout_alignParentLeft="true"
android:text="Image1" />
</RadioGroup>

<RadioGroup
android:id="@+id/rg2"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="vertical" >

<RadioButton
android:id="@+id/radioButton3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="30dp"
android:text="Image3" />

<RadioButton
android:id="@+id/radioButton4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/radioButton3"
android:layout_alignBottom="@+id/radioButton3"
android:layout_alignParentRight="true"
android:text="Image4" />
</RadioGroup>
</LinearLayout>

<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:text="Change Image" />

<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/button1"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_below="@+id/button1"
android:layout_marginTop="50dp"
android:src="@drawable/ic_launcher" />

</RelativeLayout>