How can I get ALAsset object in - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info after making photo?
You can't. An ALAsset is a representation of an entry in the photo albums somewhere. You only get them when you add the assetsLibrary framework (obviously) and enumerate the albums.
The camera doesn't create an ALAsset, they're only representations of media in photo albums