I have seen a lots of people losing their iPhone photos after they upgrade or after updating their software. There is a really easy way to avoid losing them. Sign up for a free Dropbox account. Once you signup online you can get the free iPhone app (they probably have one for Android also). Then you just follow the instructions below to always have a backup of your iPhone photos.
-First sign up at Dropbox.com. You will get 2gb of free space. No strings attached.
-Second, get the dropbox app from the itunes app store. (it's also free)
-Enter your username & password that you created when signing up from your computer.
-Then go to Settings to turn on camera uploads.
-From there you will turn on camera uploads. (I also turn on use cellular data)
-This is what it looks like once you upload your photos.
-You will need to open the app every week or so to make sure all your images have uploaded. It usually only takes a couple minutes to upload a few images. One tip on the initial upload- I would do your first upload attached to wifi. Like me, you probably have a lot of photos on your phone. You don't want to use your data plan for that initial upload.
-This is a cloud based backup service, so you will always have access to your photos as long as you have internet. Log in to your account and go to your "Camera Uploads" folder and there are all your photos.
I hope this helps and if you have any questions about this or need help setting it up, let me know...