Question

A product team is building a feature that lets users upload two photos of a damaged package—one showing the front label and one showing the dented side—and asks Claude to describe the differences between them in a single response. Using the Messages API, how should the developer structure the request so Claude can compare both images at once?

Accepted Answer

Include both images as separate content blocks within the same user message, followed by a text block asking Claude to compare them.

Answer

Send two separate API requests, each with one image, and manually merge the two responses in application code.

Answer

Encode both images into a single content block and place the comparison instruction in the system prompt.

Answer

Put the images in the assistant role so Claude treats them as prior context and the user message as the question.