I would like to upload photos from my SGS4 to my Google+ without sharing to anyone. How do I do that?
If you turn on the "Auto Backup" feature of Google+, your photos will automatically be uploaded and will only be viewable by you (until you share them, of course).
If you want to do it manually, simply share with G+ and choose yourself as the only person you share with. I like to keep a Circle around with no one in it that I can share things to and so I'm the only one who can see them (kind of a "read it later" thing). You might prefer to do that, since it's quicker to choose a Circle to share to than a person.
I was looking to do the same thing. If you want another way to do it other than adding yourself to your own circle (seems dumb to have to do that) or using Auto backup (this sucks because it does ALL your photos, what if you only want certain ones and also want them in a specific album then I have to move them after the upload) you can use the app Picasa Tool for Google + Photos in the Google Play Store. Just select your photos in Gallery and share then select Picasa Tool and you can Choose an existing album or new one, resolution size and also if you want them to be private. Everything one would want and expect for the upload experience. Google needs to get with it.