If you want more storage for your iPhone or if you keep getting the pop up alert that your storage is full, then follow this guide to purchase more storage meaning you are free to continue taking photos etc. as you wish!
Step 1 - If you're using iOS 8 or later, go to ‘Settings’ then ‘iCloud’ and then go into the ‘Storage’ menu. If you're using an earlier version of iOS, go to Settings > iCloud > Storage & Backup.
Step 2 - Tap the ‘Buy More Storage’ or ‘Change Storage Plan’ option.
Step 3 - Choose whichever upgrade you think you need, then tap Buy and enter your Apple ID password. The payment will usually come out each month automatically and will be ongoing.