The Vertical Thumbnail Image Slider is a sleek and modern gallery component built entirely with HTML, CSS, and vanilla JavaScript. This component allows users to scroll through vertically aligned thumbnails and preview the selected image in a larger view, making it perfect for product showcases, portfolio galleries, and e-commerce previews.

With a smooth user experience, elegant transitions, and no reliance on external libraries, this slider is lightweight, responsive, and easy to customize. Users can switch images by clicking on thumbnails or using the ▲ / ▼ navigation buttons, while the currently active thumbnail is highlighted with scaling and a border effect.

Ideal for developers and designers looking to implement a vertical gallery layout that fits seamlessly into dashboards, modals, or detail pages.

🔑 Key Features

• Fully responsive and mobile-friendly layout

• Vertical thumbnail navigation

• Active image highlighting with scaling effect

• Navigation buttons for manual scrolling

• Auto-scroll selected thumbnail into view

• Clean and customizable UI

• No external dependencies – built with pure HTML/CSS/JS

• Perfect for product galleries, portfolios, and admin panels