I managed it:

alias: Frigate - Notification
description: ""
trigger:
  - platform: mqtt
    topic: frigate/events
condition:
  - condition: template
    value_template: "{{ trigger.payload_json[\"type\"] == \"end\" }}"
action:
  - service: notify.jabber
    data:
      title: "Kamera {{trigger.payload_json['after']['camera']}} "
      message: >-
        Objekt {{trigger.payload_json['after']['label']}} erkannt von Kamera
        {{trigger.payload_json['after']['camera']}}.
      data:
        path: >-
          /mnt/sandisk1TB/frigate/clips/{{trigger.payload_json['after']['camera']}}-{{trigger.payload_json['after']['id']}}.jpg

I managed it:

alias: Frigate - Notification
description: ""
trigger:
  - platform: mqtt
    topic: frigate/events
condition:
  - condition: template
    value_template: "{{ trigger.payload_json[\"type\"] == \"end\" }}"
action:
  - service: notify.jabber
    data:
      title: "Kamera {{trigger.payload_json['after']['camera']}} "
      message: >-
        Objekt {{trigger.payload_json['after']['label']}} erkannt von Kamera
        {{trigger.payload_json['after']['camera']}}.
      data:
        path: >-
          /mnt/sandisk1TB/frigate/clips/{{trigger.payload_json['after']['camera']}}-{{trigger.payload_json['after']['id']}}.jpg

The Name of the Entinität in englisch is: image.ipcamsouth_Person. frigate Person detection.

I know how to send images with xmpp. The problem is that the file name changes with every new snapshot. The entity image.ipcamsued_Person contains this current snapshot.

The question now is: how can I send the contents of this entity via xmpp. Do I have to read it out first and save it as a jpg?

I use the core Integration (yaml). I'm on tchncs.de

I have solved the problem. The png files had root as owner. chown solved the problem.

This never bothered xmpp. matrix seems to be very sensitive...

yes, I did that.

I can send a jpg in this folder. But no png.

  host: 192.168.1.x
  user: xxxx
  password: xxxx

cameras:
  Gartenhaus: # <------ Name der Kamera
    ffmpeg:
      hwaccel_args: preset-vaapi
      inputs:
        - path: rtsp://xxyyy# RTSP Pfad der Kamera
          roles:
            - detect
            - rtmp
            - record
            - snapshots
    objects:
      track:
        - person
        - dog
        - cat
    detect:
      width: 640 # <---- Auflösung des gewählten RTSP Streams
      height: 352 # <---- Auflösung des gewählten RTSP Streams
    record:
      enabled: True
      retain:
        days: 7
        mode: active_objects
    snapshots:
      enabled: True
      retain:
        default: 10
        mode: active_objects
        objects:
          person: 15
##############################################################################
  AP-Garage: # <------ Name der Kamera
    ffmpeg:
      hwaccel_args: preset-vaapi
      inputs:
        - path: rtsp:// # <----- RTSP Pfad der Kamera
          roles:
            - detect
            - rtmp
            - record
            - snapshots
    objects:
      track:
        - person
        - dog
        - cat
    detect:
      width: 640 # <---- Auflösung des gewählten RTSP Streams
      height: 480 # <---- Auflösung des gewählten RTSP Streams
    record:
      enabled: True
      retain:
        days: 7
        mode: active_objects
    snapshots:
      enabled: True
      retain:
        default: 10
        mode: active_objects
        objects:
          person: 15
detectors:
    coral:
      type: edgetpu
      device: usb
##### Birdseye #######
######################
birdseye:
  enabled: True
  restream: True
  height: 1080
  width: 1920
  mode: objects```