Add images directly into gallery from Flickr or other source (not media library)

Hello,
I am hoping to create slideshows and directly import images from Flickr or another source (where I can get creative commons images). There seems to be no easy way to do this and the only option I see available it to add images directly from my computer or media library. There are plugins that will allow me to add creative commons images from various sources directly to my posts with the correct attribution, but then how do I easily translate those posts into slideshows? Is there an easy way to do this without having to find images to save to my computer, add to media library, note all of the attribution separately, then create a gallery?
Any advice would be appreciated!
Thanks
Taste Crushing

http://wordpress.org/plugins/nextgen-gallery/