Image Booru
An Image Booru is a form of image repository website for subjects such as anime (Danbooru), My Little Pony Friendship Is Magic (Ponibooru), ect.
These sites often have a tagging system in which users sort the images into categories while uploading: e.g. [X character], [X show], [X artist]
Image Boorus often differ from Image Boards--but are still closely related--by nature of simply viewing many images and occasionally commenting on them as opposed to starting a comment thread with an image and continuing in the same thread with more images.