Lesson: Don't put nude pictures of yourself on the internet.
A simple google search:http://support.apple.com/kb/PH12519?viewlocale=en_US&locale=en_US
What iCloud backs up
You have important information on your iPhone, iPad, and iPod touch. iCloud automatically backs up your device over Wi-Fi every day while it’s turned on, locked, and connected to a power source. With your device information backed up in iCloud, you can easily set up a new device or restore information on one you already have.
Here’s what iCloud backs up:
Purchase history for music, movies, TV shows, apps, and books
Your iCloud backup includes information about the content you have purchased, but not the purchased content itself. When you restore from an iCloud backup, your purchased content is automatically downloaded from the iTunes Store, App Store, or iBooks Store. Some types of content aren’t downloaded automatically in all countries, and previous purchases may be unavailable if they have been refunded or are no longer available in the store. For more information, see the Apple Support article iTunes in the Cloud availability by country. Some types of content aren’t available in all countries. For more information, see the Apple Support article Which types of items can I buy in my country?.
Photos and videos in your Camera Roll
So it's VERY plausible that they simply did not know that the photo would be backed up on iCloud and had thought they deleted it off their iPhone/iPad/Mac, whichever device had the photo.
And since this did in fact involve iCloud, they didn't just put it out there on the internet.
Might want to give some people a break before passing judgement, just saying.