Q: I cannot get my iphone6s to backup to icloud.

To perform iCloud backups, your iPhone must be:

• Turned on
• Plugged in to a power source
• On a WiFi network
• Locked

Does your iPhone fulfill all these requirements during the entire duration of the backup process?

How many pictures/videos do you have on your iPhone?

My only guess is that your backup file is larger than your available iCloud storage. Although it seems not Apple-like not to give you that information, maybe it's worth to double check.

On your iPhone go to Settings > iCloud > Backup > and try clicking on Backup Now. Does it work there?

If you have imported all the pictures to your computer like from the normal digital camera (regular copy and paste or via some photos app) nothing will be deleted from your computer.

Also, you you can try to subscribe to the 50GB iCloud Plan. It costs only $0.99 a month, so even if it doesn't help, you won't lose that much money   But if you have 2000+ pics, my bet is the storage.

monarchpapillion wrote:

But I'm concerned that what I delete on my iPhone also gets deleted on my computer, where I've downloaded them.

Do you have iCloud Photo Library enabled? If so I suggest you read this article before deleting any pictures. If you delete them on one device you will delete your synced pictures on the computer (but not your imported pictures).

iCloud Photo Library FAQ - Apple Support

My pleasure....