diff --git a/src/client/MarkdownHtml.tsx b/src/client/MarkdownHtml.tsx
index 70011ab..9f25286 100644
--- a/src/client/MarkdownHtml.tsx
+++ b/src/client/MarkdownHtml.tsx
@@ -10,9 +10,10 @@
  * Security posture: every HTML string (block leaves, inline text, wrapper
  * open-tag attributes) goes through DOMPurify with an explicit denylist on
  * top of its defaults (no script/style/iframe/forms), anchors are forced to
- * open in a new tab with noopener, and local media `src` attributes are
- * rewritten through the session-scoped `/sidebar/file` media route — the same
- * trust fence the markdown image rewriter (`markdown-images.ts`) uses.
+ * open in a new tab with noopener, and local media goes through the
+ * session-scoped `/sidebar/file` media route — markdown-syntax image
+ * destinations are rewritten via `markdown-images.ts` and `src` attributes
+ * through `resolveLocalMediaDest` (the same trust fence).
  */
 import { useLayoutEffect, useMemo, useRef } from 'react'
 import { createElement, type ReactNode } from 'react'
@@ -21,7 +22,7 @@ import { MarkdownText } from '@deepseek-ai/dsh-client-ui-primitives'
 import type { ComponentType } from 'react'
 import { markdownTextProps } from './markdown-labels.tsx'
 import { lazyChunkComponent } from './lazy-chunk.tsx'
-import { resolveLocalMediaDest } from './markdown-images.ts'
+import { resolveLocalMediaDest, rewriteLocalImageUrls } from './markdown-images.ts'
 import {
   analyzeHtmlSegment,
   type AnalyzedMarkdownHtml,
@@ -235,7 +236,12 @@ export function MarkdownDocument({ info, media, codeLabels }: MarkdownDocumentPr
   const prepared = useMemo<PreparedSegment[]>(() => info.segments.map((segment): PreparedSegment => {
     if (segment.kind === 'markdown') {
       const defs = info.referenceDefinitions
-      const text = defs === '' ? segment.text : `${segment.text}\n\n${defs}`
+      const raw = defs === '' ? segment.text : `${segment.text}\n\n${defs}`
+      // MarkdownText drops non-http(s) image destinations (chat-security
+      // stance), so rewrite local ones into /sidebar/file media URLs first —
+      // the same trust fence the sanitized HTML leaves below go through.
+      // Idempotent: already-absolute media URLs pass through untouched.
+      const text = rewriteLocalImageUrls(raw, media.scope, media.path, media.origin)
       return {
         kind: 'markdown',
         text,
diff --git a/src/client/TextEditor.tsx b/src/client/TextEditor.tsx
index 459eaf0..865a034 100644
--- a/src/client/TextEditor.tsx
+++ b/src/client/TextEditor.tsx
@@ -346,9 +346,11 @@ export function TextEditor(props: FileViewerProps) {
     () => (markdown && mode === 'preview' ? splitMermaidBlocks(previewMdText) : []),
     [markdown, mode, previewMdText],
   )
-  /** Raw-HTML analysis (block runs lifted out + inline gate). Non-null only
-   *  for documents that actually contain HTML — plain markdown keeps the
-   *  legacy single-pass render path below, byte-for-byte. */
+  /** Raw-HTML analysis (block runs lifted out + inline gate). Non-null for
+   *  every markdown preview, so the render below always takes the split
+   *  renderer — its markdown runs rewrite local image destinations internally
+   *  (see MarkdownHtml.tsx). The legacy single-pass branches (fed the
+   *  pre-rewritten `previewText`) are dead in the current wiring. */
   const htmlInfo = useMemo(
     () => (markdown && mode === 'preview' ? analyzeMarkdownHtml(previewMdText) : null),
     [markdown, mode, previewMdText],
diff --git a/tests/markdown-html-render.spec.tsx b/tests/markdown-html-render.spec.tsx
index 8e0ca9d..662152a 100644
--- a/tests/markdown-html-render.spec.tsx
+++ b/tests/markdown-html-render.spec.tsx
@@ -175,3 +175,51 @@ describe('MarkdownDocument (inline pass)', () => {
     await unmount(root)
   })
 })
+
+describe('MarkdownDocument (local markdown images)', () => {
+  it('renders markdown-syntax local images through the /sidebar/file route', async () => {
+    const { container, root } = await renderDocument([
+      '# Title',
+      '',
+      '![icon](./assets/icon.svg)',
+      '',
+      '![logo][logo]',
+      '',
+      '[logo]: ./logo.png',
+    ].join('\n'))
+    const imgs = [...container.querySelectorAll('img')]
+    expect(imgs.length, 'both local images must render as <img>, not alt fallback').toBe(2)
+    expect(imgs[0]?.getAttribute('src')).toBe('http://gui.origin/sidebar/file?sessionId=s1&path=%2Fws%2Fdocs%2Fassets%2Ficon.svg&cwd=%2Fws')
+    expect(imgs[0]?.getAttribute('alt')).toBe('icon')
+    expect(imgs[1]?.getAttribute('src')).toBe('http://gui.origin/sidebar/file?sessionId=s1&path=%2Fws%2Fdocs%2Flogo.png&cwd=%2Fws')
+    expect(imgs[1]?.getAttribute('alt')).toBe('logo')
+    await unmount(root)
+  })
+
+  it('renders local markdown images in HTML-mixed documents (the production path)', async () => {
+    const { container, root } = await renderDocument([
+      '<div align="center">badges</div>',
+      '',
+      '![shot](./img.png)',
+    ].join('\n'))
+    const img = container.querySelector('img')
+    expect(img, 'the markdown-syntax image after an HTML run must render').not.toBeNull()
+    expect(img?.getAttribute('src')).toBe('http://gui.origin/sidebar/file?sessionId=s1&path=%2Fws%2Fdocs%2Fimg.png&cwd=%2Fws')
+    await unmount(root)
+  })
+
+  it('keeps remote image destinations untouched', async () => {
+    const { container, root } = await renderDocument('![r](https://example.com/x.png)')
+    const img = container.querySelector('img')
+    expect(img?.getAttribute('src')).toBe('https://example.com/x.png')
+    await unmount(root)
+  })
+
+  it('is idempotent for already-rewritten media URLs', async () => {
+    const url = 'http://gui.origin/sidebar/file?sessionId=s1&path=%2Fws%2Fdocs%2Fimg.png&cwd=%2Fws'
+    const { container, root } = await renderDocument(`![a](${url})`)
+    const img = container.querySelector('img')
+    expect(img?.getAttribute('src')).toBe(url)
+    await unmount(root)
+  })
+})