It takes way too many clicks to get from a Flickr photo page to the original JPEG file. I wrote a bookmarklet that does it with just one click.
To install, drag the following link to your bookmarks toolbar: View Originl
To use, simply navigate to a Flickr photo page and click the bookmarklet.
I believe the bookmarklet is simple enough not to be copyrightable. However, in case it is copyrightable, I place it in the Public Domain. If that is not legally possible, I grant everyone a perpetual, royalty-free, world-wide license to treat it as if it was in the Public Domain. There is absolutely no warranty, and I disclaim all liability for anything.
Built with the help of Bookmarklet Builder.
{var images=document.getElementsByTagName("img");var src=null;for(var i=0;i<images.length;i++){if(images[i].className=="reflect"){src=images[i].src;}}var index=src.indexOf(".jpg");var original=src.substring(0,index)+"_o.jpg";window.location=original;})()){kind=link}