Thumbnail Summarization Techniques for Web Archives

Thumbnails of archived web pages as they appear in common browsers such as Firefox or Chrome can be useful to convey the nature of a web page and how it has changed over time. However, creating thumbnails for all archived web pages is not feasible for large collections, both in terms of time to create the thumbnails and space to store them. Furthermore, at least for the purposes of initial exploration and collection understanding, people will likely only need a few dozen thumbnails and not thousands. In this paper, we develop different algorithms to optimize the thumbnail creation procedure for web archives based on information retrieval techniques. We study different features based on HTML text that correlate with changes in rendered thumbnails so we can know in advance which archived pages to use for thumbnails. We find that SimHash correlates with changes in the thumbnails (ρ = 0.59, p < 0.005). We propose different algorithms for thumbnail creation suitable for different applications, reducing the number of thumbnails to be generated to 9% – 27% of the total size.