• Create an app and get an API key here: https://www.flickr.com/services/apps/create/

• Put your API key and API secret inside the flickr_download.py script (line 11 and line 12).

• This script uses an API Kit provided here: https://github.com/sybrenstuvel/flickrapi/

• To install this kit, download the project from the url provided and run the following:
  python setup.py install

• Now, the script can be run as follows:
  python flickr_download.py <user_id> <access_type>
<user_id> is the NSID of the user account from which the files will be downloaded from. This can be seen in the Flickr url of the photos page of the user (https://www.flickr.com/photos/ <user_id> /).
  <access_type> can be private or public. No authentication is required for downloading public files of any user. Authentication is required for downloading the private files (files which are in camera roll but not in public view).
  When private <access_type> is chosen, a browser window opens asking the user to authorize the app. This authorization is shown for the user who is logged in at that time on Flickr in the browser (not necessarily for the <user_id> provided). Therefore, you should logout of the Flickr account (if it is different from the one for which <user_id> is provided) from the browser before running the script.
  This kind of authorization only needs to be done once for a particular <user_id>.

• All the downloads are stored in a folder named flickr_downloads.

• The files are stored in folders corresponding to albums in Flickr. Each folder is named as the folder_id which was returned by the Flickr API. Each folder has a metadata file which contains the properties of the corresponding album as returned by the Flickr API in XML format (this includes the album name).

• Each file is named in the following format:
  <file_id>_<file_secret>_o.<extension>
  Here, <file_secret> is different from the one in the metadata. This is because <file_secret> for the original size image is different from the other sizes. '_o' at the end signifies that the image is of original size.
  Similar to folders each file has a metadata file which contains the properties of that file (this includes the original file name).

• For downloading all the files without maintaining the album structure run the other script as follows:
  python flickr_download_all.py <user_id> <access_type>