Image in gridview repeating when I scroll

Question

When I start to scroll my view. Its repeating the Image but when I click it open correct image. I tried many solutions but still I can't able to fix it. I tried many thing in converView. But it keep on repeating the image and place it in view.

  @Override
public View getView(int position, View convertView, ViewGroup parent) {

    ImageView imageView;
    View v;
    if (convertView == null) {
       /* LayoutInflater inflater = (LayoutInflater) context.getSystemService(     Context.LAYOUT_INFLATER_SERVICE );
        v = inflater.inflate(R.layout.gridview_item_layout, parent, false);
*/
        imageView = new ImageView(context);
        if(images.get(position).contains(".jpg"))
        {
            bm = BitmapFactory.decodeFile(images.get(position)); //Creation of Thumbnail of image
        }

        else if(images.get(position).contains(".mp4"))
        {
            bm = ThumbnailUtils.createVideoThumbnail(images.get(position), 0); //Creation of Thumbnail of video
        }

        imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
        imageView.setPadding(8,8,8,8);
        imageView.setLayoutParams(new GridView.LayoutParams(300, 300));


    } else {

        imageView = (ImageView) convertView;


    }
    imageView.setImageBitmap(bm);


return imageView;
}
 }