Translations:Manual:$wgAllowExternalImages/18/en

Additionally, this allows the embedding of external images which change from time to time, or are generated on request, such as graphs from monitoring software such as Cacti--if the images can be identified as image files by their extension. If embedding is enabled, it is also possible to make embedded images links using the syntax [Link_URL Embedded_Image_URL], which will cause clicks on the image to link to the Link_URL.