Thank you for your answer!
I use a precondition for my prompt:
"Use my prompt as “Revised prompt” without changes; I don’t want you to change the prompt.
Prompt: …
"
And then, the revised prompt does not change. It really works. But I still have a different image for each try.
I suggest that we need to have something like a seed parameter in the chat completions API to reach more deterministic results. Or it can be gen_id as one of the parameters in the API call.
Because in one of the previous versions, I had the same result for each try with the same prompt.