Backup your Gmail account. Backup your Flickr account. Backup any free service you're using. Otherwise, you have no one to blame but yourself when the rug gets pulled out.
Edit: or start paying for them, as a sibling comment said.
a 1 week notice, with a, say, $40 plan (or even just $40 for the first year with a higher rate later) would probably have had a lot of grumbling, but people who wanted their images back 'on' various sites would be more inclined to pay $40 to make the problem go away. For many folks, $400 is just... beyond their ability to pay immediately.