Administrators on Commons can now use UploadWizard to grab freely licensed photos directly from Flickr. Go to Special:UploadWizard, and you should see, next to the "Select a media file to donate" button, a button that lets you "Add images from Flickr".
Commons administrators, please test this and let us know how it works! I believe we want to be able to open it up so all users will be able to upload multiple images at once from Flickr to Wikimedia Commons.
(in Bugzilla: https://bugzilla.wikimedia.org/show_bug.cgi?id=28731)
wikitech-ambassadors@lists.wikimedia.org