I am having the same issue. Glad its not me but please fix. 

Yes. That was the problem. Thanks for a quick response!

Check that the URL includes www.  For me anyway, addresses without the www load (the browser displays the page) but the download script doesn't seem to recognize it as a flickr page. When I put www. in front of flickr.com the links start working properly.  For example:

https://flickr.com/photos/manfredi90/  <== does NOT work

https://www.flickr.com/photos/manfredi90/ <== DOES work

This also seems to be the case with individual photos:

https://flickr.com/photos/manfredi90/49841734451/in/dateposted/ <== does NOT work

https://www.flickr.com/photos/manfredi90/49841734451/in/dateposted/ <== DOES work

Hope that works for you,

-J

download button disappeared on image pages.