Download Entire Album from Google Plus
Here's the trick :
1. Make sure that you have Picasa installed in your computer
2. Go to the profile page of the person who has uploaded the album
3. Now copy the series of digits from addressbar [see screenshot below]
5. Paste the series of digits you copied at the end of the address. Hit enter.
6. Enter your Google+ username and password (if prompted).
6. This will open up the "Picasa Web Album" of that person. Locate the album you wish to download.
7. Click on the album and it will open up. Click on the "Download" button and select "Download to Picasa".
8. Firefox : In case a "Launch Application" window pops in, select "Picasa"
Chrome : In the "External Protocol Request" window, click "Launch Application"
9. Click "Download"
Thats it! Now enjoy the album from your local hard drive :)