When uploading to photo sharing sites - beware!
I just finished
moving my photo collection OUT of the cloud and I have to say, getting my 33,000+ photos BACK from Flickr (which is relatively open, as cloud photo services go) was not an easy task.
Cloud photo storage is plagued by compression and data loss (
picasa), by warrantless unrecoverable deletion (
Flickr - of a paid account! and obviously - Facebook) and other reliability/survivability problems.
Personally, as an avid photographer, I can't sleep soundly unless my photos are backed up in at least three places, one of the offsite. I accomplish this using a local mirrored drive, and the great cloud backup service -
crashplan.
A mirrored drive would be tricky in your case, but you could use a USB hard drive connected to a family member/friends always-on computer. Back up to that using either the crashplan client (which is free for such uses, and works great) or rsync, syncback or any other homebrew solution. Pair that with a cloud backup service, and you should be fine.
Most importantly, never relay on the cloud as your single backup strategy - the internet is full of horror stories of people who THOUGHT they had everything backed up in the cloud... a USB drive sitting at a friends place is much easier to verify.