<?xml version="1.0" encoding="utf-8" ?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"> 
 
 <ImageView android:id="@+id/image_view"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />
 
</LinearLayout>

package com.jonsegador.examples.externalimage;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.Toast;
 
public class Main extends Activity {
    private ImageView imageView;
    private Bitmap loadedImage;
    private String imageHttpAddress = "http://jonsegador.com/wp-content/apezz.png";            
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        imageView = (ImageView) findViewById(R.id.image_view);       
        downloadFile(imageHttpAddress);
    }
 
    void downloadFile(String imageHttpAddress) {
        URL imageUrl = null;
        try {
            imageUrl = new URL(imageHttpAddress);
            HttpURLConnection conn = (HttpURLConnection) imageUrl.openConnection();
            conn.connect();
            loadedImage = BitmapFactory.decodeStream(conn.getInputStream());
            imageView.setImageBitmap(loadedImage);
        } catch (IOException e) {
            Toast.makeText(getApplicationContext(), "Error cargando la imagen: "+e.getMessage(), Toast.LENGTH_LONG).show();
            e.printStackTrace();
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.jonsegador.examples.externalimage"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".Main" android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>    
    </application>
    <uses-sdk android:minSdkVersion="3" />  
    <uses-permission android:name="android.permission.INTERNET" />
</manifest>