If I have deleted photos from camera roll and then charged phone/ backed up are the photos gone? I can't seem to find them in iCloud? If so what is the point of iCloud?
Photo retrieval
iPhone 4S, iOS 8.3, Icloud
About backups in iCloud and iTunes - Apple Support
Restore your device from an iCloud or iTunes backup - Apple Support
If you don't have a backup, or haven't imported the images, they're gone. If you do have a backup, read the articles.