Retrieve parent class within morph relationship

I have this code

//ImageableTrait
trait ImageableTrait
{
    public function images()
    {
        return $this->morphMany(Image::class, 'imageable')
            ->orderBy('order', 'ASC');
    }
}

//User
class User extend Model
{
    use ImageableTrait;
}

//Post
class Post extend Model
{
    use ImageableTrait;
}

class ImageCollection extends Collection
{
    public function firstOrDefault()
    {
        if ($this->count() === 0) {
            $image = new Image();
            $image->id = 'default';
            $image->imageable_type = '/* I need the parent className here */';
            $image->imageable_id = '.';
        }

        return $this->first();
    }
}

//Image
class Image extend Model
{
    public function imageable
    {
        return $this->morphTo();
    }

    public function newCollection(array $models = [])
    {
        return new ImageCollection($models);
    }

    public function path($size)
    {
        //Here, there is some logic to build the image path and it needs
        //the imageable_type attribute no matter if there is
        //an image record in the database or not
        return;
    }
}

I want to be able to do so

$path = User::find($id)->images->firstOrDefault()->path('large');

But I can't figure out how to get the parent class name to build the path properly...

I tried with $morphClass or getMorphClass() but can't figure out how to use it properly or if it is even the right way to do it.

Any thoughts on that?

via Chebli Mohamed