Set image tag in pictrs section to 0.5 and change to the new ENV format described in the docs of pictrs. At last start only the pictrs container docker compose up -d pictrs

Here is my example in the new formaz. Be aware it is just an example ☝🏻

pictrs:
    image: asonix/pictrs:0.5
    container_name: lemmy-pictrs
    # this needs to match the pictrs url in lemmy.hjson
    hostname: pictrs
    # we can set options to pictrs like this, here we set max. image size and forced format for conversion
    # entrypoint: /sbin/tini -- /usr/local/bin/pict-rs -p /mnt -m 4 --image-format webp
    environment:
      - PICTRS_OPENTELEMETRY_URL=http://otel:4137
      - PICTRS__SERVER__API_KEY=redacted
      - RUST_LOG=info
      - RUST_BACKTRACE=full
      - PICTRS__MEDIA__VIDEO__VIDEO_CODEC=vp9
      - PICTRS__MEDIA__ANIMATION__MAX_WIDTH=256
      - PICTRS__MEDIA__ANIMATION__MAX_HEIGHT=256
      - PICTRS__MEDIA__ANIMATION__MAX_AREA=65536
      - PICTRS__MEDIA__ANIMATION__MAX_FRAME_COUNT=400
    user: 991:991
    volumes:
      - ./volumes/pictrs:/mnt:Z
    restart: always
    logging: *default-logging
    deploy:
      resources:
        limits:
          memory: 690m