Hi Benjamin Sultan,
Based on your query, I believe you need to run the detect_objects API on an image in a container, but not available publicly. As per the specification of the API, the Image URL parameter expects a publicly reachable URL of an image, so it can not work on your private images passed to it as URL.
Refer:
If you can not make your image publicly available, you may use Dected Objects in a Stream API. In this, you may pass Image data to the API. from your code, you may extract the binary data of the image in your container and then pass it to the API.
Hope this helps