An information element can reference more than one image or external link, but currently only a single image (ImageURI) can be stored and shown. This is visible when importing legislation from wetten.overheid.nl: a single article or table may contain several illustrations, of which only the first is captured today (see related ticket 4863). Extend the model and UI so an element can carry multiple images/URLs, and update the importers (e.g. Dutch law) to capture them all, and the diagram/documentation rendering to display them.