Photos and media files use up a lot of space on the internal memory of your iPhone. The more of these sorts of data you save, the faster the memory will fill up. This is why backing up or moving these files to iCloud  is strongly suggested. This will free up more space on your iPhone's internal storage, allowing it to handle additional processes and services without slowing down.

1. Go to the main menu and select 'Home.'
2. Go to the Settings tab.
3. At the top of the list, tap your Apple ID.
4. To sign in, enter your Apple ID if requested.
5. To continue, tap iCloud.
6. Select Photos.
7. Toggle the iCloud Photo Library slider to the on position.
8. To return to the previous screen, tap iCloud.
9. Scroll down to the iCloud Backup app at the bottom of the list and hit it.
10. Tap iCloud Backup to enable it if it isn't already enabled.
11. To begin the backup process for your photographs, tap Back Up Now.