You can save photos & download albums using Google+. The people who have access to see your photos or the people who you share photos / albums with also can download your photos using Google+. However, if you make changes to your share settings then they may not be able to do so. Anyways, to download photos using Google+, follow the process below:
To download one single photo
Download one of your photo albums
- Go to Google+.
- Click the photo > More > Download photo.
Downloading shared photos of albums
- Open Google+. Place your cursor in the top left corner for the Google+ main menu.
- Click Photos icon Photos.
- Click More at the top > Albums > the album you'd like to download.
- Click the drop down arrow at the top right > Download.
- From your stream or someone's profile, click on the name of the shared album you'd like to download.
- Click the drop down icon > Download album.