Shoppers pick a colour, not a dropdown row. Map any OpenCart option value to a hex colour or an image once, and every product that uses that value renders visual swatch buttons on the product page instead of a plain select or radio list. The original form field stays in the page and is kept in sync on every click, so the stock add-to-cart, price updates and option validation keep working untouched — no core file edits and no theme surgery. Option values that are out of stock are shown struck through instead of silently disappearing, so shoppers can see the colour exists and simply is not available right now. An optional display-only strip of miniature swatches can be added to category and search product cards so the available colours are visible before the click.