Optimize cold-start / image pull duration

[msundman78]

I have a small Node.JS app running in ACA where I'd like to use the scale to 0 feature but minimize the "Cold Start" time as much as possible. I'm using ACR for hosting my containers. Both app and ACR running in Sweden Central region.

Using the node:18 my image was 480 MB, Curl time_total = 30 sec, ImagePull time = 20 sec.
Switching to node:18-alpine reduced the image size to 140 MB, Curl time_total = 15 sec, ImagePull time = 7 sec

In the system logs I see a log message like this on every cold start:
Successfully pulled image 'msncsr1.azurecr.io/aitest3:20240217194821700482' in 7.3539818s

I've tried upgrading my ACR from Basic->Standard->Premium but it doesn't change the ImagePull time.

So, my question is, what can I do to further optimize the ImagePull and total Cold Start time? Is there no Image layer caching in ACA so I could benefit from using commonly used images?