Extension:PageImages

The PageImages extension collects information about images used on a page.

Its aim is to return the single most appropriate thumbnail associated with an article.

API
The PageImages extension provides image information by adding a  to the Properties API for.

Parameters:
 * piprop: What information about the page images to return (can be one or more values, pipe-delimited):
 * thumbnail - URL of image thumbnail.
 * name - Image title.


 * pithumbsize: Width of thumbnail in pixels. If omitted a default of 50px will be used.
 * pilimit: Number of pages to process.
 * picontinue: If more information is available, use this parameter to request it.

Sample request:

Configuration
$wgPageImagesBlacklist is an array of sources for image blacklists. Blacklisted images will never be selected as page images. Examples: More than one source can be used at the same time.

$wgPageImagesBlacklistExpiry determines how long the blacklist will remain cached, in seconds. Default: 15 * 60 (15 minutes).

$wgPageImagesExpandOpenSearchXml if set to true, PageImages will override the image detection in the  API module with its own, more accurate results. Default: false.

$wgPageImagesNamespaces is an array of namespaces PageImages will be activated on. Default: NS_MAIN.

The blacklist itself can be created with a simple bullet-list of file links, e.g. w:en:MediaWiki:Pageimages-blacklist contains:

How it works
When a page is saved with a local image, the parser runs the hooks  and. The PageImages extension responds to these (and other hooks) and inserts a new property for the page into the page_props table. The property name is  and its value is the name of the image.

The extension only stores the chosen image name. Other features may display the image, such as Page information, Hovercards, and Mobile search while typing.

Image choice
The page image is chosen based on a number of criteria with limited documentation. It attempts to return only meaningful images, e.g. not those from maintenance templates, stubs or flag icons. Non-free images may be skipped for copyright reasons. Images with very different width and height may be skipped due to poor display in features using the image. The first image satisfying certain criteria may be chosen. No image will be chosen on some pages.