I’ve been meaning to do this for ages and I finally got around to it.
My Chrome Extension, Rule of Thirds, has finally been updated to fix the circles so that they are drawn fully again and I also added a fix to ignore images that are styled to be hidden (display: none). This fixes the issue on the new Flickr single page view where two grids were displayed (the offset one was displayed over a low resolution image that is hidden once the high resolution image is loaded).
If you haven’t already installed it then please head over to the Chrome Web Store and check it out:
if you want to look at the source code then that’s on GitHub: