Hey Holycow852,
I understand that you have recently upgraded your computer to OS X El Capitan and hopefully your iOS devices as well. You are currently having issues with syncing your photos to each device. Let's see if we can get this sorted out.
If you you have done the upgrades to both systems, check to see if you are using iCloud Photo Library.
- On your iOS device, tap Settings > iCloud > Photos.
- On your Mac, click Photos > Preferences > iCloud.
If you are using it on just one device, then you will start to have issues with syncing.
If you have this turned on for all your devices, then it will sync your photos without having to plug in a sync with your computer.
If you have this turned off, then you should be able to sync by using iTunes to move photos to your computer. If you are importing then, you should see your devices in Photos for import.
Check out the article below for more details.
iCloud Photo Library FAQ
https://support.apple.com/en-us/HT204264
Take it easy