
Now we should thanks to the developers who has give their contributions to make Google+ more stylish so we can overcome this problem using a little application they have made.
This application is used as an extension in Google Chrome web browser, so you'll need to download and install the Google Chrome first to activate this application. Visit Google Chrome website to learn more.
Actually I found several good applications related to zooming/enlarging photos in Google Plus. But, I prefered to use one as my favorite. This Google Chrome extension is called +Photo Zoom.
+Photo Zoom is a simple extension providing fast and simple zooming for photos within your Google+ Stream. Just hover over the image you wish to zoom and +Photo Zoom will load the enlarged version of the picture.
All you need is visit Chrome Web Store from your Google Chrome web browser then Download +Photo Zoom for Google Chrome
Click on Add to Chrome blue button on the right side. After Chrome finished download the file, from "+Photo Zoom - Options" window click on Settings tab to set up your extentions.
Now you can start exploring the photos in enlarged on Google Plus. Enjoy!