Memory issues in fragments showing images

I am using fragments to show images/pages.I have one Activity(Main) which contains all the fragments.

package com.example.hscroll.demo;

import android.os.Bundle;
import android.preference.PreferenceManager;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.app.ListFragment;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;

import com.crittercism.app.Crittercism;
import com.example.hscroll.customer.BitmapWeakReference;
import com.example.hscroll.customer.PromotionalPriceListAdditionsDataAdaptor;
import com.example.hscroll.customer.PromotionalPriceListDataAdaptor;
import com.example.hscroll.library.imagezoom.ImageViewTouch;

public class MainAct extends FragmentActivity{

private ImageViewTouch  mImageView;
MyPagerAdapter mPagerAdapter;
ViewPager viewPager;
 static final int NUM_ITEMS = 58;

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState); 
    Crittercism.init(getApplicationContext(), "4f391d0fb09315319d00048d");
    PreferenceManager.setDefaultValues(this, R.xml.preference, false);

    setContentView(R.layout.viewpager_layout);

    mPagerAdapter = new MyPagerAdapter(getSupportFragmentManager());

    viewPager = (ViewPager)findViewById(R.id.viewpager);
    viewPager.setAdapter(mPagerAdapter);
}


public static class MyPagerAdapter extends FragmentStatePagerAdapter {
    public MyPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public int getCount() {
        return NUM_ITEMS;
    }

    @Override
    public Fragment getItem(int position) {
            return newInstance(position);
    }


}

static Fragment newInstance(int position) {

    Fragment data = null;
    switch(posi