PHImageManager throws exception while generating image - ios

Question

I have this problem. When I try to generate image from asset using this method:
manager.requestImageForAsset(asset, targetSize: CGSize(width: asset.pixelWidth, height: asset.pixelHeight), contentMode: .AspectFit, options: option, resultHandler: {(result, info)->Void in
thumbnail = result!
As you can see I have put in the target size the width is "asset.pixelWidth" which I believe it returns the actual width of the asset, therefore I want the generated image to have the same dimensions as the original asset.
For some reason this throws an exception "unexpectedly found nil while unwrapping an Optional" on some images in my camera roll, Not all of them, but some of them. What is more interesting is that when I put the target size 100 for example for both width & height. It works on all assets on camera roll without exceptions.
Honestly I don't understand what the heck is happening here. So if can someone give me a clue that would be great.
This is the whole method used:
func getFullAssetImg(asset: PHAsset) -> UIImage {
let manager = PHImageManager.defaultManager()
let option = PHImageRequestOptions()
var thumbnail = UIImage()
option.synchronous = true
print(asset.pixelWidth)
print(asset.pixelHeight)
manager.requestImageForAsset(asset, targetSize: CGSize(width: asset.pixelWidth, height: asset.pixelHeight), contentMode: .AspectFit, options: option, resultHandler: {(result, info)->Void in
thumbnail = result!
})
return thumbnail
}
and this is how it's called:
let image = self.getFullAssetImg(asset)
--------UPDATE--------
When I added an option with value:
options.deliveryMode = .FastFormat
It worked! if I make this option with value HighQualityFormat it will throw exception
It's working now but if any one can tell me how this option solved my problem that could help other people.

Answer 1

Dears,
After spending one whole day i at last know whats happening here:
Thanks to this link: PHImageManager.requestImageForAsset returns nil
I noticed an option called networkAccessAllowed. This options makes the manager able to process an image on the cloud.
What was going wrong was that i was testing an image that was based on icloud so it was returning nil.
However this is the last piece of code I got to make things work:
func getFullAssetImg(asset: PHAsset) {
let manager2 = PHImageManager.defaultManager()
print(asset.pixelWidth)
print(asset.pixelHeight)
//let imageSize = CGSize(width: asset.pixelWidth, height: asset.pixelHeight)
let options = PHImageRequestOptions()
options.deliveryMode = .FastFormat
options.synchronous = true
options.networkAccessAllowed = true
manager2.requestImageForAsset(asset, targetSize: PHImageManagerMaximumSize, contentMode: .AspectFit, options: options, resultHandler: {(result, info)->Void in
if let thumbnail = result{
self.fullResolutionImages.addObject(thumbnail)
print("Full Resolution Image Added")
}
})
}
Hope it helps someone afterwards.
Thank you