RequestImage's result handler called twice - ios

Question

I have an array of image assets. I have to turn those assets into images, add them to an array and upload them to Firebase Database. I have 2 issues with this.
Issue 1:
In a custom UICollectionViewCell I display all the images that the user has selected, I see 4 images in the cell, when I've selected 4 images from the Photos (I'm using a custom framework). Now, when I call requestImage method, I get double the amount of images in the array that's supposed to convert each asset from the asset array and store it into a UIImage array called assetsTurnedIntoImages. I read more about it and it's related to the PHImageRequestOptions and if its isSynchronous property returns true or false, that or if PHImageRequestOptions is nil. Now, obviously I didn't get something because my code still doesn't work.
Issue 2:
As you can see from the code below, the targetSize gives me a somewhat thumbnail image size. When I upload the image to the storage, I don't need a thumbnail, I need it's original size. If I set it to PHImageManagerMaximumSize I get an error:
"Connection to assetsd was interrupted or assetsd died”
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell
{
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "PhotoPostCVCell", for: indexPath) as! PhotoPostCVCell
if let takenImage = cameraPhotoUIImage
{
cell.cellImage.image = takenImage
}
if assets.count > 0
{
let asset = assets[indexPath.row]
let requestOptions = PHImageRequestOptions()
requestOptions.isSynchronous = true // synchronous works better when grabbing all images
requestOptions.deliveryMode = .opportunistic
imageManager.requestImage(for: asset, targetSize: CGSize(width: 100, height: 100), contentMode: .aspectFill, options: requestOptions)
{ (image, _) in
DispatchQueue.main.async {
print("WE ARE IN")
cell.cellImage.image = image!
self.assetsTurnedIntoImages.append(image!)
}
}
}
return cell
}

Answer 1

Change the option could solve the problem:
options.deliveryMode = .highQualityFormat
I found that solution in the source code:
#available(iOS 8, iOS 8, *)
public enum PHImageRequestOptionsDeliveryMode : Int {
#available(iOS 8, *)
case opportunistic = 0 // client may get several image results when the call is asynchronous or will get one result when the call is synchronous
#available(iOS 8, *)
case highQualityFormat = 1 // client will get one result only and it will be as asked or better than asked
#available(iOS 8, *)
case fastFormat = 2 // client will get one result only and it may be degraded
}

Answer 2

To avoid completion handler's twice calling, just add an option in this request to make it synchronous
let options = PHImageRequestOptions()
options.isSynchronous = true
let asset: PHAsset = self.photoAsset?[indexPath.item] as! PHAsset
PHImageManager.default().requestImage(for: asset, targetSize: CGSize(width: 1200, height: 1200), contentMode: .aspectFit, options: options, resultHandler: {(result, info) in
if result != nil {
//do your work here
}
})
To avoid crash on loading image you should compress the image or reduce its size for further work