Live Content SlideShow module includes Flickr support. Simply specify the Flickr feed URL and the slideshow will be auto created...

In the demo above, you can see beach, flowers, carribean, and fountains pictures. Following Flickr feed was used:
http://api.flickr.com/services/feeds/photos_public.gne?tags=flowers,nature,beach,fountains&tagmode=any

You can learn more about composing the feed url at http://www.flickr.com/services/feeds/

The demo has a random transition applied and pictures are stretched to fit the area.

Note: Live Content dependence is not required when using the module with Flickr support; however, you must have Live Content installed on the portal.