invalid MountType: "image"

Deploying to a swarm cluster does not work with volume type=image.

docker -H ssh://swarm.lan stack deploy -c compose.yaml test

Got: failed to create service test_with_image: Error response from daemon: invalid MountType: "image".

services:
  with_image:
    image: alpine
    command: "sleep 3600"
    deploy:
      replicas: 1
    volumes:
      - type: image
        source: nginx:alpine
        target: /mnt/image
        image:
          subpath: usr/share/nginx/html/  # https://github.com/moby/swarmkit/issues/3182
               

Client: Docker Engine - Community
 Version:           28.1.1
 API version:       1.49
 Go version:        go1.23.8
 Git commit:        4eba377
 Built:             Fri Apr 18 09:52:57 2025
 OS/Arch:           linux/amd64
 Context:           default

Server: Docker Engine - Community
 Engine:
  Version:          28.1.1
  API version:      1.49 (minimum version 1.24)
  Go version:       go1.23.8
  Git commit:       01f442b
  Built:            Fri Apr 18 09:52:57 2025
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.7.27
  GitCommit:        05044ec0a9a75232cad458027ca83437aae3f4da
 runc:
  Version:          1.2.5
  GitCommit:        v1.2.5-0-g59923ef
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

Start by reproducing the issue with the shown docker stack deploy command and compose.yaml, then trace how the image volume mount is converted for swarm services before Docker Engine validation. Done means a service using type=image with the shown source, target, and subpath can be deployed successfully to a swarm cluster.