There are times when some one just send you a link to flickr image and you can actually see that image just because flickr is blocked in your college or office work place. In such a case you actually enable a lab feature in your gmail account where you can see the preview thumbnail of the flickr picture without opening it.
Follow the procedure to enable the flickr preview in gmail
1. Go to gmail.com and go to gmail account settings as shown in the image below.
2. Under settings, click the labs link to explore the labs features, scroll down and locate Flickr Previews and Enable by checking the option to enable it as shown in the image below.
3. Once you select the enable option, scroll down to locate the button Save Changes and click it.
Now you will see flickr previews for the flickr photo links you receive in mail as shown in the image below.