Importing templates has been an important feature since the beginning, but to date it’s been limited to copy/paste, or importing from a URL. We now support importing from local files, and specifically to import from zip files containing HTML & plain text files, including the related images.
This is a common format used by third-party email template creation tools, and also used in exports from various other ESPs. We automatically apply format conversions so that templates designed for other ESPs can work as expected – though of course you should always test before committing to a big send.
In brief – you can import HTML templates including functionality and images in one click.