Android ListView image flickers while trying to load the image from SQLite Database

I implemented ListView to display some items from the SQLite Database. Each of which contains an Image and some Data.

I want my ListView to work faster even if it contains thousand rows of data. So i tried to implement some optimizations that i have noticed. Here is the basic structure of my CustomCursorAdapter:

Class CustomCursorAdapter extends CursorAdapter
{
    Cursor cursor;
    public CustomCursorAdapter(..., Cursor _cursor)
    {
        cursor = _cursor;
    }

    public void bindView(View _view, Context _context, Cursor _cursor)
    {
        if( view.getTage() == null)
        {
            //create and initialize a new holder and set it to view tag.
            holder = new Holder();
            ...
            ...
            holder.imageView = (ImageView) view.findViewById(R.id.image);
            holder.imageView.setImageDrawable(defaultDrawable);

            view.setTag(holder);
        }

        String mediaID = _cursor.getString("media_id");

        //create an asyncTask to load the image from database
        new MediaLoader(context, holder.imageView).execute(mediaID);
    }

    private class MediaLoader extends AsyncTask<String, Void, Media>
    {
        private Context context;
        private final WeakReference <ImageView> imageViewReference;

        public MediaLoader(Context _context, ImageView _imageView)
        {
            context = _context;
            imageViewReference = new WeakReference<ImageView>(_imageView);
        }

        protected Media doInBackground(String... args)
        {
            String _mediaID = args[0];  
            return MediaDataManager.getInstance(_context).getMediaObjectForListAdapter(_mediaID);
        }

        protected void onPostExecute(final Media _media)
        {
            super.onPostExecute(_media);

            if( imageViewReference != null )
            {
                ImageView _imageView = imageViewReference.get();

                if(_imageView != null)
                {
                    if( _media != null && _media.getImage() != null )
                    {
                        _imageView.setImageBitmap(_media.getImage());
                    }
                    else
                    {
                        _imageView.setImageDrawable(defaultDrawable);
                    }
                }
            }
        }
    }//Media Loader ends.
}//Custom Cursor Adapter Ends.

Using this approach loading time of image seemed ok to me.

But in some android devices (low configuration ones), i am experiencing image flickering. For some reason during scrolling or even loading i noticed images keeps changing throughout the list. But the final image that remains in every row is always the correct one.

I couldn't find any helpful resource by searching. Any kind of help is very much appreciated.