A few months ago I discovered that Flickr has no security for images. Flickr has a nice feature which allows users to assign variable levels of copyright protection on images, from full copyright to various Creative Commons licenses. Images with less restrictive licenses show an "All Sizes" link which will let visitors download the image in various sizes. Images with full copyright do not show this link.
This isn't much of a problem as long as only people with enough technical knowledge to look at the source code of a page can find the images, but I suspect there will be a good number of Flickr users who be a bit upset when anyone can download their full-size copyrighted images with a single click. It is with my sympathies for these users that I publish the following bookmarklet that you can click when viewing any image page on Flickr to get the original full-size version of that image:
My goal here isn't to facilitate the downloading of images that Flick users don't want downloaded, but rather to point out that Flickr has already facilitated such downloading. This is a public service announcement: Flickr has no image security.