Openai api gpt4 vision => default value / behavior of "detail" param

I have been struggling with the usage of the “detail” param in the gpt4 vision API.

it looks like I finally managed to understand how to use it now.

But I would like to know what is the default value, or basically what happens when you do NOT use it.

documentation => OpenAI Platform
referers to either “low” or “high” without stating which one is the default value.

in the code (python openai v 1.2.0) =>
it basically says :
detail: Literal[“auto”, “low”, “high”]
“”“Specifies the detail level of the image.”“”

I’m kinda guessing that “auto” is probably the default value, but I’m not sure. And even if I was, I don’t really know what’s happening under the hood.

Can someone please help me out in understanding this?