Not just the Android phone users, even iPhone users can upload photos on Google+ using any app that can send pictures to Google’s image organizer, Picasa.
Unless the native app is available for the iPhone, Paul Molluzzo of Alpha Dad, suggests how you can upload pics on Google+, using an ad-supported app called Piconhand, available for free on the App Store.
After you have downloaded and installed the app, sign in with your Google credentials. It’ll show you a list of your existing albums.
Find Location Service by tapping the settings icon, then Location Service, and then scroll down to find Piconhand.
Create a new “Mobile Uploads” album or name it a Circle that you would like to have access to it. This enables you to have control over who sees the pictures in Google+.
The app also allows you to edit the pics if choose that in preference.
Once the picture is uploaded, go to Google+ and adjust the visibility of the album where you have uploaded those pics, assigning that folder to the various circles you would like to share it with.
Unless Apple approves a Google+ app for iOS, as Mashable reports this is the quickest and easiest way to send photos to Google+.
The iOS app is completed and submitted to App store awaiting of approval.