What are favorites?
Favorites are photos by other people that you want to bookmark in Flickr, so they are easy to find later. You can add any photo that you can view to your favorites.
There is no limit on the number of favorites you can have.
How do I mark a photo as one of my favorites?
On the photo's individual page, click the 'Favorite' button at the bottom right corner of the photo.
Voila! (To remove a favorite, click that button again.)
Can I mark my own photos as my favorites?
No. Favorites are just a handy way to make note of photos you like that are published by other people. To collect your own favorite photos, you could make yourself a set. Just go to the Organizr, create a new set and add your photos to it.
Can other people see my favorites?
Yes. When another person looks at your favorites, they will only see all the public photos in your collection, and any photos they uploaded, regardless of the privacy.
How do I delete a photo from my favorites?
Go to 'Your favorites' and click on the photo you'd like to remove. Click the pink star button on the photo to remove it from your favorites.