Image Delivery Service (IDS)

What does the Image Delivery Service offer?
What is the static delivery?
What is the dynamic delivery?
What digital files are required?
Captions for still images
Setting maximum delivery size
Image Delivery Service Documentation

If you need more information or assistance with IDS, contact IDS support staff.


What does the Image Delivery Service offer?

The Image Delivery Service (IDS) delivers digital images that are stored in the Digital Repository Service (DRS) to web browsers. In general, images available through this service have been converted from photographs, slides, prints, and other two-dimensional media held in special collections throughout the University. IDS can secure images to the Harvard community (i.e., those with a Harvard ID number and PIN) when appropriate. The Image Delivery Service has two flavors: static image delivery and dynamic image delivery.

What is static delivery?

Static delivery allows web access to an image in the DRS, similar in functionality to putting an image on a web server. Most commonly used for JPEG and GIF images, this method can deliver any image deposited in the DRS back to an end-user. This service currently delivers many of the digital images described in the VIA catalog, but it can also serve images cataloged in HOLLIS, OASIS, or any other catalog or web site that supports URL linking.

Here's an example.

What is dynamic delivery?

Dynamic delivery allows delivery of many different versions of a particular image, ranging from a thumbnail to beyond a full-size screen image, back to the user from a single file in the DRS. This feature can greatly diminish the number of images deposited in the DRS for the same functionality as static delivery. Dynamic delivery also gives users access to an interactive interface for exploring the image, which includes the ability to zoom, pan and rotate.

Here's an example of four versions of an image: thumbnail, small, medium and large as well as the interactive interface — all rendered dynamically from one file in the repository.

What digital files are required?

Delivery Type File Type Deposited in DRS File Type Delivered to Users
Static JPEG, GIF, TIFF Same as deposited*
Dynamic JPEG2000 (JP2) JPEG

* IDS can deliver TIFFs "as is" (not as GIF). If the browser has a plugin that displays TIFF images (e.g. Quicktime) they will be displayed in the browser, otherwise it will prompt for an application to view them.

Captions for still images

DRS collection curators can request that captions be applied to still images stored in the DRS and delivered by the Image Delivery Service. See Image Captions [pdf] for more information.

Setting maximum delivery size

The default maximum size for digital images delivered by the Image Delivery Service (IDS) is 2400 pixels in the largest dimension. But curators can set a lower maximum delivery size for their images on a per-billing-code basis. See Image Delivery Size Restriction [pdf] for more information.

Image Delivery Service Documentation