Normally, you can save pictures from Flickr (or any website) by right clicking the photograph and saying "Save Image As.." but in the case of protected Flickr images, all you will see on the desktop is a blank 1x1 pixel placeholder image called spaceball.gif
When a Flickr member has set download permissions to disallow his/her photos from being downloaded, a transparent image is overlaid on the actual photo so the right-click method fails.
How to Download Private Flickr PhotosYou may either use the good-old Print Screen or any of the methods listed below to bypass the Flickr image protection:
For Firefox: Goto Tools -> Page Info -> Media - Scroll down until you see that Flickr image in the Media Preview Window. Click the Save As button.
In IE, Opera, Safari or Firefox: Right click the Flickr web page and chose "View HTML source" - now search for "spaceball.gif" in the HTML source. You'll find the full location of the protected image enclosed in the <img src=".."> tag just before the tag that encloses the spaceball image.
You can also download Flickr Images in a batch or refer to this Flickr Guide for more related tools.