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.

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.

Issue #1210396 by saulalbert, aaron: Fix Notice: Undefined property: stdClass:: in media_flickr_file_styles_filter().