- (void)dropImageShadow {
CGMutablePathRef path = CGPathCreateMutable();
CGRect pathrect = CGRectMake(imageView.center.x - imageView.image.size.width/2,
imageView.center.y - imageView.image.size.height/2,
imageView.image.size.width,
imageView.image.size.height);
CGPathAddRect(path, NULL, pathrect);
previewImage.layer.shadowPath = path;
CGPathRelease(path);
}