Recreate the layout and functionality demonstrated below. After laying out the assets with HTML and CSS, be sure to prototype the desired outcome. Use your browser's tools to arrive at a solution, before beginning the JavaScript code necessary to implement that solution.
For each thumbnail clicked, modify the document such that the primary image holds all the necessary information to both display the image clicked in larger form, but also remain accessible (for example, ensuring the alt attribute of the large images matches the imagery shown).