If you own a Flickr account you should probably change your password the minute you read this post. Yahoo says that the data breach occurred in late 2014 and “The account information may have included names, email addresses, telephone numbers, dates of birth, hashed passwords (the vast majority with bcrypt) and, in some cases, encrypted or unencrypted security questions and answers“.
This does not mean that your Flickr password was necessarily stolen (and if it was, it is not that easy to un-hash hashed passwords), but you should probably change your password just to be safe. Especially if this user/password combo is used for more than Flickr.
You can read more about this breach on Yahoo’s FAQ.
P.S. in case you are looking for an alternative, here are some self hosted options for you.