You want to send a screenshot to a vision model. All three of the big ones — OpenAI's GPT-4o, Anthropic's Claude, Google's Gemini — accept images the same fundamental way: Base64-encode the bytes and put them in the JSON request. No file uploads, no multipart, just text in a payload.
Source: [Dev.to](https://dev.to/pjanderson/sending-images-to-gpt-4o-claude-and-gemini-the-base64-payload-each-one-wants-1iei)