Favicons
When you add a bookmark, the site’s favicon is fetched. If one is found, it is compressed into a base64 data URL in the bookmarks file. This ensures that Pinax can remain offline and that there are no external requests after the initial fetch.
OG Images
If the “Automatically fetch web data” setting is enabled, Pinax will fetch Open Graph images for bookmarks as they are rendered in grid view. These images are stored in a cache directory.