android - Add image from cache-memory to android wallpaper

Question

I have application where images downloads from internet (arrays.xml) and then shown in Pager Adapter consequentially. I need to set the desired image to android wallpaper with help button. But i don't understand how add image from cache-memory to wallpaper (image not stored on the SDcard) ? Images downloading from arrays.xml file:

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string-array name="heavy_images">
        <item>https://images-url.com/01.jpg</item>
        <item>https://images-url.com/02.jpg</item>
        <item>https://images-url.com/03.jpg</item>
        <item>https://images-url.com/04.jpg</item>
        <item>https://images-url.com/05.jpg</item>
 </string-array>

</resources>

Then images shown in Pager Adapter:

import android.os.Bundle;
import android.os.Parcelable;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.Toast;

public class ImagePagerActivity  extends BaseActivity  {

    private ViewPager pager;

    private DisplayImageOptions options;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.ac_image_pager);

        Bundle bundle = getIntent().getExtras();
        String[] imageUrls = bundle.getStringArray(Extra.IMAGES);
        int pagerPosition = bundle.getInt(Extra.IMAGE_POSITION, 0);

        options = new DisplayImageOptions.Builder()
            .showImageForEmptyUri(R.drawable.image_for_empty_url)
            .cacheOnDisc()
            .imageScaleType(ImageScaleType.EXACT)
            .build();

        pager = (ViewPager) findViewById(R.id.pager);
        pager.setAdapter(new ImagePagerAdapter(imageUrls));
        pager.setCurrentItem(pagerPosition);

            }

    @Override
    protected void onStop() {
        imageLoader.stop();
        super.onStop();
    }

    private class ImagePagerAdapter extends PagerAdapter {

        private String[] images;
        private LayoutInflater inflater;

        ImagePagerAdapter(String[] images) {
            this.images = images;
            inflater = getLayoutInflater();
        }


        public void destroyItem(View container, int position, Object object) {
            ((ViewPager) container).removeView((View) object);
        }


        public void finishUpdate(View container) {
        }


        public int getCount() {
            return images.length;
        }


        public Object instantiateItem(View view, int position) {
            final FrameLayout imageLayout = (FrameLayout) inflater.inflate(R.layout.item_pager_image, null);
            final ImageView imageView = (ImageView) imageLayout.findViewById(R.id.image);
            final ProgressBar spinner = (ProgressBar) imageLayout.findViewById(R.id.loading);

            imageLoader.displayImage(images[position], imageView, options, new ImageLoadingListener() {

                public void onLoadingStarted() {
                    spinner.setVisibility(View.VISIBLE);
                }


                public void onLoadingFailed(FailReason failReason) {
                    String message = null;
                    switch (failReason) {
                        case IO_ERROR:
                            message = "Input/Output error";
                            break;
                        case OUT_OF_MEMORY:
                            message = "Out Of Memory error";
                            break;
                        case UNKNOWN:
                            message = "Unknown error";
                            break;
                    }
                    Toast.makeText(ImagePagerActivity.this, message, Toast.LENGTH_SHORT).show();

                    spinner.setVisibility(View.GONE);
                    imageView.setImageResource(android.R.drawable.ic_delete);
                }


                public void onLoadingComplete() {
                    spinner.setVisibility(View.GONE);
                    Animation anim = AnimationUtils.loadAnimation(ImagePagerActivity.this, R.anim.fade_in);
                    imageView.setAnimation(anim);
                    anim.start();
                }


                public void onLoadingCancelled() {
                    // Do nothing
                }
            });

            ((ViewPager) view).addView(imageLayout, 0);
            return imageLayout;
        }


        public boolean isViewFromObject(View view, Object object) {
            return view.equals(object);
        }


        public void restoreState(Parcelable state, ClassLoader loader) {
        }


        public Parcelable saveState() {
            return null;
        }


        public void startUpdate(View container) {
        }
    }
}

ac_image_pager.xml

<?xml version="1.0" encoding="utf-8"?>
        <android.support.v4.view.ViewPager
     xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/pager"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" />

item_pager_image.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" 
    android:padding="1dip">

    <ImageView
        android:id="@+id/image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:adjustViewBounds="true" />

    <ProgressBar
        android:id="@+id/loading"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:visibility="gone" />

</FrameLayout>

Thanks.