Flickr's Community Guidelines say that you're supposed to upload your own work (http://www.flickr.com/help/guidelines/ http://www.flickr.com/help/guidelines/):

Flickr's Community Guidelines say that you're supposed to upload your own work (http://www.flickr.com/help/guidelines/ http://www.flickr.com/help/guidelines/): > Don’t upload anything that isn't yours. This includes other people's photos, video, and/or stuff you've copied or collected from around the Internet. Accounts that consist primarily of such collections may be deleted at any time.