Image source: Los Angeles County Museum of Art (LACMA) Image Library.
The default parameter, an integer, completes the URL of an artwork record on LACMA's web site, in the form
alternate_url parameter can be used to point directly to the page from which the file is downloaded (to confirm that the image has been released into the public domain) in the following two cases:
- Some of the standard artwork record pages do not specify that a "Public Domain High Resolution Image [is] Available", even though the site from which they are ultimately downloaded does. The high-resolution public domain files are accessed on a different web server with the entry point http://www.lacma.org/image-library. If an image is available here, it is part of "a selection of unrestricted high resolution images from LACMA's collection", and the download page itself will specify "Public Domain High Resolution Image" (PDHRI). An example is File:Andrea Vaccaro - David with the Head of Goliath.jpg, where the regular record page does not specify PDHRI, but the file is available from the download server, which does specify PDHRI.
- Some images available on the download server do not have corresponding record pages on the regular web site (e.g. File:Pacetti, Camillo - Allegory of Peace.jpg — a search for the artist on the regular web site yields no results but the image exists on the download server with a PDHRI notation).
The ability to confirm the museum's release is strictly relevant only for images that would not normally be public domain in the Template:PD-Art sense.