Every 5 minutes flickr is searched for new photos tagged with the word "favcol".
Each photo is then checked to ensure we can use it. This is done in one of two ways:
If the "favcol" tag was added by the owner of the photo then we assume this gives us permission to use it.
If anyone else added the tag we check the photo's license - if it has a Creative Commons license allowing derivative works then we use the photo.
If neither of these are true, we ignore the photo.
It can take a couple of minutes for photos to get through the system, so be patient.
If you think a photo has been missed out, or you'd like a photo removed, get in touch.