The CIC Metadata Portal The CIC Metadata Portal
The CIC Metadata Portal

Thumbnails/Thumbshots
CIC Metadata Portal > Thumbnails/Thumbshots

Use of Thumbnail and Thumbshot Images in Metadata Aggregation Services

read the full article: Automated Capture of Thumbnails and Thumbshots for Use by Metadata Aggregation Services

get the software: UIUC OAI Metadata Harvesting Project at Sourceforge

The practice of adding thumbnail images and web-page screen captures to the search results of metadata aggregation service providers is becoming more common. The inclusion of these images in brief-record search results is intended to assist users in determining the relevance of resources quickly and efficiently. The CIC Metadata Portal has implemented some methods for obtaining and including thumbnails and thumbshots in the context of OAI.

Currently, OAI-PMH does not provide guidelines on collection and use of these images, and there is no consensus on how to alert metadata aggregators of their availability. The CIC portal uses two approaches:

  1. Distributed thumbnails - Data providers would add a metadata element to convey the URL of a thumbnail or graphic surrogate of the resource being described.
  2. Remotely captured thumbnails - As part of routine metadata harvesting and processing, thumbnails and thumbshots would be created by the service provider using the resource URLs provided in metadata records harvested.

The primary difference between the two approaches is that the former requires additional work on the part of the data provider (while giving them control over thumbnail generation and quality), and the latter is the responsibility of the service provider.

Thumbgrabber, an open source application, was developed to capture, generate, and maintain thumbnails and thumbshots from Web resources referenced in descriptive metadata. It supports 3 different methods which specify which image resources will be captured. The application can be made to capture largest image only, HTML webpage only, or largest image or HTML webpage. The latter method checks for the existence of an image of adequate dimension; if one exists it captures a thumbnail of the image otherwise a thumbshot of the entire Webpage is created. Thumbgrabber then uses image manipulation tools to scale the images down to thumbnail size, convert them to a PNG image, and save them to disk. Thumbgrabber is written in Visual Basic and makes use of the programming interface of Microsoft Internet Explorer® (MSIE) and can be downloaded from the UIUC OAI Metadata Harvesting Project page on SourceForge.net.

example thumbnail example thumbshot

Using and managing thumbnails and thumbshots should be a collaborative process between data providers and service providers. Data providers need to be aware that thumbnails and thumbshots are one of the ways in which digital library services are taking advantage of graphical presentation of their resources, and should help in the creation and use of these images.

For more information on this topic, please see "Automated Capture of Thumbnails and Thumbshots for Use by Metadata Aggregation Services" (Muriel Foulonneau, Thomas G. Habing, Timothy W. Cole) in D-Lib Magazine (January 2006, Volume 12 Number 1).