Rule of Thirds

Name: Rule of Thirds
Rating: 4.4 (20 reviews)
Author: Ivor Potter

Simple extension to draw a 3 x 3 grid on an image to help visualise the Rule of Thirds.

As of May 2026, Rule of Thirds has 5,000 users and a 4.40/5 rating from 20 reviews in the art category.

Ivor Potter art

Chrome Web Store ↗.crx

Users0%

5.0K

5,000

Rating0%

4.40

20 reviews

Reviews0%

Version

1.7

Manifest V3

Permissions & access

Permissions: scriptingactiveTabstorage
Host access: None declared

Screenshots

About

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.

History
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v1.7 - 2 June 2024
  * Switch from host_permissions to activeTab (extension does nothing until clicked)
  * Position grid correctly for local images (ie file:// protocol)
  * Add Options page to control grid size, colours & whether lines and/or circles are rendered
  * Support arbitrary sized grid

v1.6 - 21 May 2024
  * Migrate to Manifest v3
  * Replace JQuery dependency with native functions

v1.5 - 29 August 2014
  * Ignore images with "display: none" styles
  * Fix circles on intersection points so they are drawn fully