You can use next methods in thread.
Bitmap b1 = ThumbnailUtils.createVideoThumbnail(pathName1,
MediaStore.Images.Thumbnails.MINI_KIND);
Bitmap bmp1 = Bitmap.createScaledBitmap(b1, nWidth, nHeight, true);
And set image in main thread
imageView1.setImageBitmap(bmp1);