BSImagePicker所有图像模糊

我使用BSImagePicker而不是UIImagePicker来启用multi-select。 我正在为此使用以下代码:

    let bsImagePicker = BSImagePickerViewController()
    bsImagePicker.maxNumberOfSelections = 4

    self.bs_presentImagePickerController(bsImagePicker, animated: true, select: { (asset : PHAsset) in

    }, deselect: { (asset : PHAsset) in

    }, cancel: { (assets : [PHAsset]) in

    }, finish: { (assets : [PHAsset]) in

        for asset in assets {

            self.selectedAssets.append(asset)

            self.convertAssetsToImage()
        }

    }, completion: nil)

为了将相位集转换成图像,我使用以下代码:

func convertAssetsToImage() {

    for asset in selectedAssets {

        let manager = PHImageManager.default()
        let option = PHImageRequestOptions()
        var thumbnail = UIImage()
        option.isSynchronous = true

        manager.requestImage(for: asset, targetSize: CGSize(width: 340, height: 365), contentMode: .aspectFit, options: option, resultHandler: {(result, info) -> Void in

            thumbnail = result!
        })

        self.selectedPhotos.append(thumbnail)
    }

    DispatchQueue.main.async {

        self.imageViewImage.animationImages = self.selectedPhotos
        self.imageViewImage.animationDuration = 5.0
        self.imageViewImage.startAnimating()
    }
}

但所有的图像都是模糊的。如果显示ImagePicker,则所有图像都会稍微模糊,选择后图像仍然模糊。

这是选择屏幕的图像:

这是所选图像的图像:

例如,如果我使用UIImagePicker,这是一个图像: