Zeroing ALAssetRepresentation after saving image captured via UIImagePickerController in iOS5 - ios5

Question

In my app (which worked under iOS 4) I collect pictures selected via UIImagePickerController. Unfortunately, I have a strange problem after upgrading to iOS 5.
In a nutshell, I store ALAssetRepresentation in NSMutableArray. When I add photos from Library, everything is ok. However, when I capture and save a picture, all ALAssetRepresentations (including a new one) become 0-sized. ALAssetRepresentation.size and ALAssetRepresentation.getBytes:fromOffset:length:error: return 0 and getBytes:error is nil.
I init ALAssetsLibrary in AppDelegate, so the
“The lifetimes of objects you get back from a library instance are tied to the lifetime of the library instance.” condition is OK.
Is there a way to prevent ALAssetRepresentation from zeroing? Or how can I read image by bytes after this?
My code:
-(void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{
if ([picker sourceType] == UIImagePickerControllerSourceTypePhotoLibrary){
[self addPhoto:[info valueForKey:UIImagePickerControllerReferenceURL]];
}
else if ([picker sourceType] == UIImagePickerControllerSourceTypeCamera){
[self savePhoto:[info valueForKey:UIImagePickerControllerOriginalImage]];
}
[self dismissModalViewControllerAnimated:YES];
}
-(ALAssetsLibrary*) getLibrary{
if (!library){
testAppDelegate *appDelegate = (testAppDelegate *)[[UIApplication sharedApplication] delegate];
library = appDelegate.library;
}
NSLog(#"getLibrary: %#", library);
return library;
}
-(void) addPhoto:(NSURL*) url{
ALAssetsLibraryAssetForURLResultBlock successBlock = ^(ALAsset *asset_){
ALAssetRepresentation *assetRepresentation = [[asset_ defaultRepresentation] retain];
[photos addObject: assetRepresentation];
};
ALAssetsLibraryAccessFailureBlock failureBlock = ^(NSError *error){
NSLog(#"Error: Cannot get image. %#", [error localizedDescription]);
};
[[self getLibrary] assetForURL:url resultBlock:successBlock failureBlock:failureBlock];
}
- (void)savePhoto:(UIImage *)image {
[[self getLibrary] writeImageToSavedPhotosAlbum:[image CGImage] orientation:[image imageOrientation] completionBlock:^(NSURL *assetURL, NSError *error) {
if (error) {
NSLog(#"Error: Cannot save image. %#", [error localizedDescription]);
} else {
NSLog(#"photo saved");
[self addPhoto:assetURL];
}
}];
}

Answer 1

I solved it!
ALAssetsLibraryChangedNotification
Sent when the contents of the assets library have changed from under the app that is using the data.
When you receive this notification, you should discard any cached information and query the assets library again. You should consider invalid any ALAsset, ALAssetsGroup, or ALAssetRepresentation objects you are referencing after finishing processing the notification.

Answer 2

Have you tried retaining the ALAssets instead of the ALAssetRepresentation? This should work, I have used this approach before.