Simple extension to draw a 3 x 3 grid on an image to help visualise the Rule of Thirds.
The is a simple extension to apply a 3 x 3 grid over any images found on a web page which are larger than 100px x 50px. The purpose of the grid is to help photographers visualise the Rule of Thirds.
By displaying the grid over the image it is very simple to identify if a photograph's main focal points comply with the Rule of Thirds or not.
v1.5 - 29 August 2014
* Ignore images with "display: none" styles
* Fix circles on intersection points so they are drawn fully