Android：通过php从webserver下载图像

I want to download an image from an android app. However, in the app I don't know the name of the image.

In a php script, I choose the image file that the app should download randomly and now I have two options:

1. I could echo the image file name and the app can then download the file directly
2. I could just echo the whole image data

What is the better way? And if it is the first, could you link to a good page on how to download an image? I can upload images easily but the internet is full of different ways on how to download an image, so I don't know which one is the best...

The way i did it was the first way, the image URL was stored in a database and retrieved through json along with other data, the i used the below code to get the image from the URL.

public class ImageDownloader {

public static Bitmap downloadImage(String url) throws MalformedURLException{
    return downloadImage(new URL(url));
}

public static Bitmap downloadImage(URL url){
    Bitmap bmImg = null;
    try {
    HttpURLConnection conn= (HttpURLConnection)url.openConnection();
    conn.setDoInput(true);
    conn.connect();
    InputStream is = conn.getInputStream();

    bmImg = BitmapFactory.decodeStream(is);
    } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    return null;
    }


    return bmImg;
 }  
}

It returns bitmap

public static Bitmap getImage(String url){
        Bitmap img = null ;
        try {
            URL feedImage = new URL(url);
            HttpURLConnection conn= (HttpURLConnection)feedImage.openConnection();
            InputStream is = conn.getInputStream();
            img = BitmapFactory.decodeStream(is);

        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return img ;    
    }