diff --git a/ARCHITECTURE.md b/ARCHITECTURE.md
index 3a4d0ac4a..1ae3e4a80 100644
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
@@ -64,7 +64,7 @@ flowchart LR
| `chunking.py` | Splits a document into meaning-identifiable units (paragraph, sentence, DOM, conversation-turn) plus embedded-image extraction, in document order |
| `embedding_client.py` | Pluggable text-embedding channel (`Null` default, `OpenAiCompatible` real impl) + `chunked_max_similarity` |
| `adjudication_client.py` | Pluggable LLM-judgment channel (`Null` default, `ContextualOrchestrator` real impl) |
-| `image_content.py` | Pluggable vision channel: OCR + object recognition/tagging for embedded images (`Null` default, `OpenAiCompatibleVisionClient` real impl). The product popup (`frontend/src/PostBody.tsx`) renders each `data:image` payload in document order so the buyer sees the picture, not the base64 string; GET does not call the vision client. |
+| `image_content.py` | Pluggable vision channel: OCR + object recognition/tagging for embedded images (`Null` default, `OpenAiCompatibleVisionClient` real impl). The product popup (`frontend/src/PostBody.tsx`) and `extract_base64_images` parse with the same HTML rules as `chunk_by_dom` (ADR 0020) so invoice-like `alt` values still show the picture; GET does not call the vision client. |
| `tepp_client.py` | TEPP's published `AnalysisRunRequest` wire contract, pluggable transport |
| `reconstruct.py` | The pipeline: group → candidate window → score → fuse → thread |
| `lineage_persistence.py` | Flattens reconstruct trees into `post_lineage_edge` row specs (parent, child, fused_score) |
diff --git a/CHANGELOG.md b/CHANGELOG.md
index d30ae14aa..362b240b5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,17 @@ All notable changes to this project are documented here. Format follows
[Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versioning follows
[Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+## [0.86.3] - 2026-08-16
+
+### Fixed
+
+- Opening a post whose embedded picture uses invoice-like HTML
+ (`alt="Invoice > 1000"`, unquoted `width`, newlines in the base64)
+ now shows the picture. The raw payload no longer returns when a
+ remote-only or SVG tag is the whole body. Re-export as PNG or JPEG
+ if the type is rejected. The popup, `extract_base64_images`, and
+ `chunk_by_dom` share one raster allowlist (ADR 0020).
+
## [0.86.2] - 2026-08-16
### Fixed
diff --git a/docs/adr/0020-embedded-image-html-parser.md b/docs/adr/0020-embedded-image-html-parser.md
new file mode 100644
index 000000000..aaa8bedc6
--- /dev/null
+++ b/docs/adr/0020-embedded-image-html-parser.md
@@ -0,0 +1,76 @@
+# ADR 0020 — Embedded images use an HTML parser and a raster allowlist
+
+**Decision status:** Accepted
+**Date:** 2026-08-16
+
+## Context
+
+PR #140 stopped the product popup from dumping a well-formed
+`data:image/png;base64,...` invoice as a base64 wall. The splitter and
+`extract_base64_images` still used a `[^>]*` regex. Real invoice HTML
+puts `>` inside `alt` or `title` *before* `src`. That shape is legal
+HTML (WHATWG, n.d.) and is what `chunk_by_dom` already parses. The regex
+missed the picture and put the payload back into the text node.
+
+The same open MIME class `image/[a-zA-Z0-9.+-]+` accepted
+`image/svg+xml`. SVG-as-`![]()
` does not run script in current browsers,
+but the regex also fed the vision channel. `atob` and
+`b64decode(validate=True)` already disagreed on padding.
+
+ADR 0019 is the R&R catalog-identity decision. This decision is the
+viewer/extractor parse contract.
+
+Persistence of OCR under the figure (Li et al., 2023; Radford et al.,
+2021) is still the next buyer slice. It must not land on a splitter that
+fails the HTML the buyer actually opens.
+
+## Decision
+
+The popup (`splitPostBody`), `extract_base64_images`, and `chunk_by_dom`
+share one decode helper (`lineageweave.embedded_image_payload`):
+
+1. Parse with an HTML parser (`DOMParser` in the browser, `html.parser`
+ in Python). Comments, `
+Please confirm.
diff --git a/tests/test_embedded_image_payload.py b/tests/test_embedded_image_payload.py
new file mode 100644
index 000000000..375cdfbea
--- /dev/null
+++ b/tests/test_embedded_image_payload.py
@@ -0,0 +1,44 @@
+from __future__ import annotations
+
+import base64
+
+from lineageweave.embedded_image_payload import (
+ decode_data_uri_image,
+ looks_like_raster_image,
+ source_offset,
+)
+
+_TINY_PNG_B64 = (
+ "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNk+A8AAQUBAScY42YAAAAASUVORK5CYII="
+)
+_TINY_PNG = base64.b64decode(_TINY_PNG_B64)
+
+
+def test_looks_like_raster_image_accepts_png_signature() -> None:
+ assert looks_like_raster_image("image/png", _TINY_PNG) is True
+
+
+def test_looks_like_raster_image_rejects_ascii_labeled_as_png() -> None:
+ assert looks_like_raster_image("image/png", b"Hello") is False
+
+
+def test_decode_data_uri_image_rejects_svg_and_remote_src() -> None:
+ assert decode_data_uri_image("https://example.test/invoice.png") is None
+ assert (
+ decode_data_uri_image(
+ "data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg=="
+ )
+ is None
+ )
+
+
+def test_decode_data_uri_image_accepts_newlines_inside_png_payload() -> None:
+ wrapped = f"data:image/png;base64,{_TINY_PNG_B64[:24]}\n{_TINY_PNG_B64[24:]}"
+ decoded = decode_data_uri_image(wrapped)
+ assert decoded == ("image/png", _TINY_PNG)
+
+
+def test_source_offset_maps_htmlparser_getpos() -> None:
+ source = "ab\ncd"
+ assert source_offset(source, 1, 0) == 0
+ assert source_offset(source, 2, 1) == 4
diff --git a/tests/test_image_content.py b/tests/test_image_content.py
index 033202be6..26fdd727c 100644
--- a/tests/test_image_content.py
+++ b/tests/test_image_content.py
@@ -1,9 +1,12 @@
from __future__ import annotations
import base64
+from pathlib import Path
import pytest
+from lineageweave.chunking import chunk_by_dom
+from lineageweave.embedded_image_payload import decode_data_uri_image
from lineageweave.image_content import (
ImageContentClient,
ImageDescriptionParseError,
@@ -55,6 +58,45 @@ def test_extract_base64_images_empty_document_yields_no_images() -> None:
assert extract_base64_images("No images here.
") == []
+def test_extract_base64_images_skips_svg_and_unpadded_payloads() -> None:
+ svg = (
+ '
'
+ )
+ assert extract_base64_images(svg) == []
+ assert extract_base64_images('
') == []
+ assert decode_data_uri_image(f"data:image/png;base64,{_TINY_PNG_B64}") is not None
+
+
+def test_invoice_fixture_is_one_visible_png_for_every_extractor() -> None:
+ """Outlook-style invoice HTML must not resurrect the base64 wall.
+
+ The same file is read by the TypeScript popup splitter. All three
+ extractors must see one raster PNG, ignore the commented copy, the
+ remote URL, the SVG, and the CSS background, and keep surrounding
+ sentences readable.
+ """
+ html = (Path(__file__).parent / "fixtures" / "synthetic_invoice_embedded_image.html").read_text(
+ encoding="utf-8"
+ )
+ images = extract_base64_images(html)
+ chunks = chunk_by_dom(html)
+ image_chunks = [chunk for chunk in chunks if chunk.unit_type == "image"]
+ text = " ".join(chunk.text for chunk in chunks if chunk.unit_type == "dom")
+
+ assert len(images) == 1
+ assert len(image_chunks) == 1
+ assert images[0].mime_type == "image/png"
+ assert images[0].data == base64.b64decode(_TINY_PNG_B64)
+ assert images[0].position == html.find("![)
+ assert]()
None:
content = "TEXT: Quarterly Budget Report\nCAPTION: A printed report cover page.\nTAGS: document, report, text"
description = _parse_description(content)
diff --git a/uv.lock b/uv.lock
index e1d2860cf..179628fdd 100644
--- a/uv.lock
+++ b/uv.lock
@@ -454,7 +454,7 @@ wheels = [
[[package]]
name = "lineageweave"
-version = "0.86.2"
+version = "0.86.3"
source = { virtual = "." }
dependencies = [
{ name = "certifi" },