How do I create a project with multiple files?

As of September 2015, Thimble supports multiple file projects. You can add HTML, CSS, and JavaScript files to your project’s file tree which you can access on the left side of the Thimble page.

Multi-file support allows you to create more real-world projects that span multiple files and folders, and easily include other open source code in your project. You can also add image files from your desktop directly to your project. Previously, Thimble only allowed adding web-based images.