Rule of Thirds

A customisable grid overlay for visualising image composition techniques (primarily the Rule of Thirds).

A customisable grid overlay for visualising image composition techniques (primarily the Rule of Thirds). History ------------------------------------------------------------------------------------------------------------------------ v1.8 - 20 September 2026 * Toolbar icon now shows at a glance whether the grid is on, plus a warning badge if it can't be applied * Customise grid: show/hide individual grid lines and circles * Circles can now be drawn filled, not just outlined * Colour picker: full colour spectrum, opacity sliders, and quick-pick swatches for the original 8 colours * Grid rows/columns restricted to 1-9 to avoid performance issues * Minimum image size the grid applies to is now configurable * New "Embedded Frames" option applies the grid inside iframes too * Grid now works correctly on fixed-position images * Default line colour is now white * Restore Defaults is instant with Undo, instead of a confirmation prompt 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