As the great nude selfie breach of 2014 has shown us, some of the photos that were leaked were accessed via iCloud accounts. Some of these photos were no longer on devices, and were either accessed from Photo Stream backups, or simply iCloud backups.
Security is a trade-off; if you don’t back up your device, you’ll eventually lose some of its data. John Gruber, writing on Daring Fireball, sums it up well:
“…I would wager heavily that there are thousands and thousands more people who have been traumatized by irretrievable data loss (who would have been saved if they’d had cloud-based backups) than those who have been victimized by having their cloud-based accounts hijacked (who would have been saved if they had only stored their data locally on their devices).”
If you do have compromising photos on your iOS device, you might want to turn off Photo Stream. To do this, go to Settings > iCloud, then tap Photos. You’ll see the screen at the left. Make sure My Photo Stream and Photo Sharing are turned off (the toggles will look as they do in this screenshot).
But, remember that Photo Stream is designed as both a backup and a sharing feature. If you turn it off, make sure to back up your iOS device so you don’t lose important data.