show error for validation multiple images

I would like validate multiple images.
I have this code but i have some problem for show the errors ($this->validator->getErrors())
Someone can help me please?

PHP Code:

$validationRule = ([
        'images' => [
          'uploaded[images]',
          'is_image[images]',
          'mime_in[images,image/jpg,image/jpeg,image/gif,image/png]',
          'max_size[images,4096]',
          'max_dims[images,1920,1080]',
        ],
      ]);

      if (! $this->validate($validationRule))
      {
        return redirect()->to(base_url('cck/articles'))->with('danger', ''.$this->validator->getErrors());
      } 


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