Please upload images in images manager section. Click on Manage Images button on the right side of the gallery settings.
Please make sure that you didn't enabled option: Images of the Current Gallery. Option should have Show value to show images.
Christmas 2018Christmas 2018 https://sunsportgardens.com/wp-content/themes/blade/images/empty/thumbnail.jpg 150 150 https://secure.gravatar.com/avatar/0f9735936835a117b42e21dda20475f4?s=96&d=mm&r=g