Rated 4 out of 5 stars
A small bug.
1 - Open a new private tab.
2 - Look something in google
3 - Select a piece of text, right click and select "Search Google for ..."
4 - Navigate to the new private tab (visit some sites)
5 - Close all tabs and clean via ctrl + shift + sup
6 - Run recovery software (eg recuva)
7 - Some visited images are recovering
Thanks for report.
I created an issue: https://github.com/Infocatcher/Private_Tab/issues/56
Can you confirm that this happens only for small images (with icons on the tabs)?
[Added at 2013-06-13]
Should be fixed in new version: https://addons.mozilla.org/addon/private-tab/versions/0.1.3