You don’t modify the contents of a base64 unless you want to corrupt it.
This is the format of message that must be sent to chat completions:
[
{
"role": "system",
"content": [
{"type": "text", "text": system_prompt}
]
},
{
"role": "user",
"content": [
{"type": "text", "text": "Describe this art style."},
{
"type": "image_url",
"image_url": {"url": f"data:image/jpeg;base64,{encoded_string}"}
}
]
}
]
Assistants does not accept base64 images.