How to print a message for each async loop item?

Below is a snippet from a playbook. How can I print a message after the command is run for each loop item? Something like

image.pyc is now running for item1
image.pyc is now running for item2

and so on

- name: Image Server(s)
  command: python3 image.pyc {{ item }} "{{ systemVersion }}"
  register: async_out
  async: 7200
  poll: 0
  with_items: "{{ hostinfo_input.hosts }}"

What I want is simply this

TASK [Image Server(s)] ************* 
changed: [localhost] => (item=8m007) 
changed: [localhost] => (item=8m013) 
Running image.pyc for 8m007 
Running image.pyc for 8m013

In a nutshell, extremely simple, untested, to be adapted to your use case specifically in terms of error/output control:

    - name: Image Server(s)
      ansible.builtin.command: python3 image.pyc {{ item }} "{{ systemVersion }}"
      register: async_out
      async: 7200
      poll: 0
      with_items: "{{ hostinfo_input.hosts }}"

    - name: Wait for commands to finish
      ansible.builtin.async_status:
        jid: "{{ item.ansible_job_id }}"
      register: job_result
      until: job_result.finished
      retries: 720
      delay: 10
      loop: "{{ async_out.results }}"

    - name: Show async command output
      ansible.builtin.debug:
        msg: "{{ item.stdout }}"
      loop: "{{ async_out.results }}"

   - name: Good guests always clean up after themselves
     ansible.builtin.async_status:
       jid: "{{ item.ansible_job_id }}"
       mode: cleanup
     loop: "{{ async_out.results }}"

References:

• async in playbooks
• async_status module
• debug module
• Registering variables with a loop

Have a look at Ansible documentation for the debug module: https://docs.ansible.com/ansible/latest/collections/ansible/builtin/debug_module.html

E.g.use it like this:

# playbook.yaml
---
- hosts: localhost
  connection: local
  vars:
    ip_addresses:
      - 10.0.0.10
      - 10.0.0.11
  tasks:
    - name: Task
      include_tasks: task.yaml
      loop: "{{ ip_addresses }}"

# task.yaml
---
- name: Command
  ansible.builtin.shell: "echo {{ item }}"
  register: output

- name: Message
  ansible.builtin.debug:
    msg: |
      - ip_address={{ item }}
      - ouput={{ output }}      

Unfortunately this does not work with async. See https://github.com/ansible/ansible/issues/22716.

Your requirement as it is described currently

> How can I print a message after the command is run for each loop item?

could just be fulfilled by loop output with label

> This is for making console output more readable ...

in example

---
- hosts: test
  become: false
  gather_facts: false

  tasks:

  - name: Image Server(s)
    command: "python3 image.pyc {{ item }} {{ systemVersion }}"
    register: async_out
    async: 7200
    poll: 0
    loop: "{{ ansible_play_hosts }}"
    loop_control:
      label: "Running image.pyc for {{ item }}"

resulting into an output of

TASK [Image Server(s)] *******************************************************
changed: [test1.example.com] => (item=Running image.pyc for test1.example.com)
changed: [test2.example.com] => (item=Running image.pyc for test2.example.com)
...

The given example just provides the message after the command is sent over to the Remote Node and was started there. That is simply working because it is not defined who should provide (print) the message, the loop via label, async or the script. See also the comment of @Zeitounator ...