Flickr have a function allowing users to explore images. This add
Support for these type of url. Example:
https://www.flickr.com/photos/paks/35329523855/in/explore-2017-06-15/

Provide correct link to media_flickr setting page.

 Flickr renamed photosets (sets) to albums
 https://www.flickr.com/help/forum/en-us/72157644091018883
 It also change the url from sets to albums though sets url still
 exists.

Issue #2075661 by brunodbo, steinmb, DamienMcKenna: fixed Change from using square_thumbnail to media_thumbnail

All of Flicker data sources are now https. Embedding content from non
https sources on a SSL enabled site will in most modern browsers be
blocked (mixed mode blocking).

Issue #2066485 by David_Rothstein. Download the original (largest) size photo from Flickr by default.

Issue #1728728 by aaron: allow the administrator to set flickr photos and photosets to display the image preview with a link back to flickr.

Issue #1397818 by SteffenR: Fix call to undefined function _media_flickr_photo_url() at add media from flickr.