Written by Matthew Wronka
You can group your photos into related sets in one of two ways. Once you create a set (available from the manage set link in your profile), you can manually add a photo at a time. This can become tedious if you want to create a set for a specific photo shoot or even a recent vacation.
You can tell a set to automatically add all photos taken between a time range to a set. Via the manage set page, to include any photos taken between Christmas and New Years, you could add the rule:
taken between 2012-12-24 and 2012-01-01
You aren't limited to just filters by date. Additional rules can be separated by semi-colons (';'), with other words you can use in place of 'taken' including 'focallen' and 'shutter'.