Given a docker image someone else has built, how do I make a new docker image that also has some additional files?
To create a new Docker image based on an existing image and add additional files, you can create a new Dockerfile that uses the existing image as a base image and then copies the additional files into the new image.

Here's an example:

Let's say the existing image is named `my-base-image` and you want to add a file named `additional-file.txt` to the new image.

**Create a new directory for your new image**

Create a new directory for your new image, e.g., `my-new-image`.

**Create a Dockerfile**

In the `my-new-image` directory, create a new file named `Dockerfile` with the following contents:
```dockerfile
FROM my-base-image

# Copy the additional file into the image
COPY additional-file.txt /app/additional-file.txt
```
Here, `FROM my-base-image` tells Docker to use the `my-base-image` image as the base image for your new image. The `COPY` instruction copies the `additional-file.txt` file from the current directory (i.e., the directory containing the Dockerfile) into the `/app` directory in the new image.

**Add the additional file**

Create a file named `additional-file.txt` in the same directory as the Dockerfile, with the contents you want to add to the new image.

**Build the new image**

Run the following command from the `my-new-image` directory:
```
docker build -t my-new-image.
``
To create a new docker image with additional files, you need to build the base image from the docker hub or another repository, then add your additional files to the image. You can use the docker command line to build and push the image, or use a tool like Docker Compose to manage the build and deployment process.