__block NSString *imageFileName;

 NSURL *imageURL = [info valueForKey:UIImagePickerControllerReferenceURL];

 ALAssetsLibraryAssetForURLResultBlock resultblock = ^(ALAsset *myasset) {

   ALAssetRepresentation *representation = [myasset defaultRepresentation];

   imageFileName = [representation filename];
 };

 ALAssetsLibrary* assetslibrary = [[ALAssetsLibrary alloc] init];

 [assetslibrary assetForURL:imageURL resultBlock:resultblock failureBlock:nil];