An ISO image, or ISO file, is an exact copy of an optical disk, in a single file.
ISO images are smaller duplicates of an optical disk’s data. You can use them to archive digital copies of a physical disc, and use them later when needed.
ISO images use .ISO file extension.
We do not currently support ISO images for custom images. In the meantime, if you have an ISO image you want to use, you can create a new image using your VM software of choice and save it again in a supported format. For a detailed walk-through, see How to Create a DigitalOcean Droplet from an Ubuntu ISO Format Image.