That's not how they work. The original GPT-4 paper has some detail: https://cdn.openai.com/papers/gpt-4.pdf
Or read up on PaliGemma: https://github.com/google-research/big_vision/blob/main/big_...
Or read up on PaliGemma: https://github.com/google-research/big_vision/blob/main/big_...