If you use an iPhone feel free to learn from my loss. I was gone for about five weeks to Southern Europe, and turned off my phone and all the apps so it would (hopefully) happily hibernate in my absence. Instead it DIED in my absence. 
The very unfortunate part is I lost all my photos in my phone, including all the pictures I had taken down south while snow birding this winter. Irreplaceable!
I was under the (mistaken) impression that my phone and it's contents were being backed up into the iCloud somewhere, and it/they would be relatively easy to retrieve in the case of my phones death. I found out otherwise.
The ONLY time it backs up into the iCloud is when it is BOTH charging AND simultaneously hooked to the Internet via wi-fi or other.
To save battery with it hunting wi-fi hot spots all the time, and the ongoing irritation of it constantly notifying me wi-fi is available (typically ones I am locked out of) I shut off the wi-fi feature and just left it off. I have an iPad so I don't typically use wi-fi on my iPhone at all. BIG mistake. Pictures and most everything else-GONE!
Any how, this is my current understanding of what/why. Some of you techies may want to respond to improve the accuracy. Feel free. A techie I am NOT.
The only slight silver lining is my iPhone was 8 days from being out of warranty, so Apple replaced it with a new one.

There's a setting to turn off wifi notifications - and it will automatically join only "known" networks. iCloud was very buggy from the beginning - and I never trusted it - always plugging in to a computer to do syncing and backups. Sorry for your loss of pics I know that's frustrating. If the pics on your phone, I would periodically verify the last backup - regardless of whether it happens in iCloud or on your 'puter.

Technology triumphs again! ( "I, Robot" gets a step closer every day)

Just another reason I use the ubber cheap Samsung Discovery (Android) that has a micro-SD card. Just put my pictures on the SD card and never have to worry about losing them.
I paid a whooping $69.00 for this smartphone at Radio Shack and it is smarter than me!! On the Net10 network at $45/mo with unlimited everything. I don't need no stinking apple!!!

I too have the iPhone and an IPad. I take pictures with both of them and wanted to be able to keep all pictures available for viewing on both devices.

I found an app in the App Store called PhotSync and it works great. No Mac or PC required (although you can synch to/from them if you really want to). Download and install the app on both your iPhone and iPad. Turn on the Bluetooth function on both of them. Start the PhotoSync app on both of them. Choose all or some photos and hit the sync icon. It requires you to select from a short list which way the pics are going (i.e. from what device/to what device) but nothing complex or labor/thought intensive.

It effectively backs up all your photos on your other device and in the process lets you look at all of them on both too.

(It's still a good idea to back up both phone and ipad on the cloud in the event of a worst case scenario where both devices are in a backpack dropped in the lake etc etc.)