IDS provide Level 1 support for the International Image Interoperability Framework (IIIF) Image API.
IIIF is a set of community supported APIs that allow any image viewing application that supports the standard to embed digital image content from any supporting institution in their applications. The Harvard Library Page Viewer uses this API to display highly zoomable images of page turned documents from the DRS.
The IIIF Image API is an HTTP web API that allows a user to request digital image access through URL values that specify the region, size, rotation, quality, and format of the portion of a digital image to be returned to the browser.
For the DRS Image Delivery Service, the base URL for accessing the Image API is
http://ids.liba.harvard.edu/ids/iiif/<DRS ID>
For example, the following URL displays a full size image oa a page from the DRS
http://ids.lib.harvard.edu/ids/iiif/5981222/full/pct:50/full/native.jpg
The following URL selects a region of the full size image at x=800, y=1100 with width=1000 and height=1000
http://ids.lib.harvard.edu/ids/iiif/5981222/800,1100,1000,1000/pct:50/full/native.jpg
More details on the complete API can be found at IIIF Image API.