ImageBlock carries an image source and its MIME type. The source sum type is represented by one ImageSource value with either a URL or inline bytes.

API surface

type ImageSource struct {
	URL  string
	Data []byte
}

type ImageBlock struct {
	MediaType MediaType
	Source    ImageSource
}

Field	Meaning	Valid shape
`MediaType`	MIME type such as `MediaTypeImagePNG`	Provider and caller agree on supported types
`Source.URL`	Remote image reference	Set for URL-backed input
`Source.Data`	Inline bytes	Set for inline input

The source comment says to set exactly one of URL or Data. The core package does not add a validation method, so a provider codec must reject or normalize an invalid combination at its boundary. Model.Caps.AcceptsImages is the inference-layer admission check for any image nested in messages or tool-result content.

Example

package main

import "github.com/looprig/core/content"

func main() {
	remote := &content.ImageBlock{
		MediaType: content.MediaTypeImagePNG,
		Source:    content.ImageSource{URL: "https://example.test/chart.png"},
	}
	inline := &content.ImageBlock{
		MediaType: content.MediaTypeImageJPEG,
		Source:    content.ImageSource{Data: []byte{0xff, 0xd8}},
	}
	_ = []content.Block{remote, inline}
}

The inference request validator walks all four sealed message types and nested ToolResultBlock.Content; it returns *inference.ImageInputUnsupportedError when the model does not advertise image input.

Proof

Source: core/content/block.go, core/content/media_type.go
Tests: core/content/block_json_test.go, inference/client_test.go