diff --git a/packages/webui/test/browser/harness.mjs b/packages/webui/test/browser/harness.mjs
index a7af431b..2b69ead1 100644
--- a/packages/webui/test/browser/harness.mjs
+++ b/packages/webui/test/browser/harness.mjs
@@ -56,6 +56,27 @@ export const PIXEL_BUDGET = { maxDiffPixels: 8 };
 /** Screenshot options shared by every baseline comparison. */
 export const screenshotOptions = { animations: "disabled", ...PIXEL_BUDGET };
 
+/**
+ * Waits for the shell's own asset images to settle before a baseline is
+ * taken.
+ *
+ * A screenshot records whatever is painted at that instant, and the shell
+ * draws its composer mascot from a `<picture>`: the browser starts on the
+ * poster PNG and upgrades to the WebP, and the upgrade aborts the first
+ * request. A frame taken inside that window shows the browser's broken-image
+ * placeholder instead of the picture, which is a few thousand pixels of
+ * difference that says nothing about the layout under review.
+ *
+ * The wait is on the settled state rather than on a deadline: an image that
+ * is still being fetched is not settled, and one that failed to load fails
+ * the poll with a legible message instead of a cryptic pixel diff.
+ */
+export async function waitForLocalImages(page) {
+  await expect.poll(() => page.locator('img[src^="/assets/"]').evaluateAll((images) =>
+    images.every((image) => image instanceof HTMLImageElement && image.complete && image.naturalWidth > 0),
+  )).toBe(true);
+}
+
 export async function configureFixture(page, setup) {
   await page.addInitScript({ content: `window.__WEBUI_FIXTURE_SETUP__ ??= []; window.__WEBUI_FIXTURE_SETUP__.push((${setup.toString()}));` });
 }
diff --git a/packages/webui/test/browser/plugin-catalogue-layout.spec.mjs b/packages/webui/test/browser/plugin-catalogue-layout.spec.mjs
index 736787e2..c78c6fb4 100644
--- a/packages/webui/test/browser/plugin-catalogue-layout.spec.mjs
+++ b/packages/webui/test/browser/plugin-catalogue-layout.spec.mjs
@@ -2,7 +2,7 @@ import { mkdirSync } from "node:fs";
 import { join } from "node:path";
 import { expect } from "@playwright/test";
 
-import { openApp, screenshotOptions, test } from "./harness.mjs";
+import { openApp, screenshotOptions, test, waitForLocalImages } from "./harness.mjs";
 
 test("marketplace and management keep vertical categories pinned on the left", async ({ page }) => {
   await page.addInitScript(() => {
@@ -430,6 +430,7 @@ async function expectCenteredDialog(dialog, page, fieldsSelector, expectedFields
     insideViewport: true,
     ...(fieldsSelector ? { fieldsDisplay: expectedFieldsDisplay } : {}),
   });
+  await waitForLocalImages(page);
   await expect(page.locator('[data-webui-dialog-scrim="true"]')).toHaveScreenshot(screenshotOptions);
 }
 
diff --git a/packages/webui/test/browser/responsive-baselines.spec.mjs b/packages/webui/test/browser/responsive-baselines.spec.mjs
index b3182ed1..6ebf391f 100644
--- a/packages/webui/test/browser/responsive-baselines.spec.mjs
+++ b/packages/webui/test/browser/responsive-baselines.spec.mjs
@@ -17,7 +17,13 @@
 
 import { expect } from "@playwright/test";
 
-import { configureFixture, openApp, screenshotOptions, test } from "./harness.mjs";
+import {
+  configureFixture,
+  openApp,
+  screenshotOptions,
+  test,
+  waitForLocalImages,
+} from "./harness.mjs";
 
 /** The widths the contract's matrix covers. */
 const WIDTHS = [1440, 1280, 1024, 900, 768, 640, 480];
@@ -35,6 +41,7 @@ for (const width of WIDTHS) {
     await page.setViewportSize({ width, height: 900 });
     await configureFixture(page, () => undefined);
     await openApp(page, "#session=A");
+    await waitForLocalImages(page);
     await expect(page.locator("#webui-root")).toHaveScreenshot(`shell-at-${width}.png`, screenshotOptions);
   });
 }
@@ -46,6 +53,7 @@ for (const width of PANEL_WIDTHS) {
     await openApp(page, "#session=A");
     await page.getByTestId("workspace-panel-controls").getByRole("button", { name: "浏览器" }).click();
     await expect(page.getByTestId("workspace-panel")).toBeVisible();
+    await waitForLocalImages(page);
     await expect(page.locator("#webui-root")).toHaveScreenshot(`workspace-panel-at-${width}.png`, screenshotOptions);
   });
 }
diff --git a/packages/webui/test/browser/scheduling-panel.spec.mjs b/packages/webui/test/browser/scheduling-panel.spec.mjs
index 67f47c28..26eaf83c 100644
--- a/packages/webui/test/browser/scheduling-panel.spec.mjs
+++ b/packages/webui/test/browser/scheduling-panel.spec.mjs
@@ -10,7 +10,13 @@
 // is in when they click the rail.
 import { expect } from "@playwright/test";
 
-import { configureFixture, openApp, screenshotOptions, test } from "./harness.mjs";
+import {
+  configureFixture,
+  openApp,
+  screenshotOptions,
+  test,
+  waitForLocalImages,
+} from "./harness.mjs";
 
 test.describe("the scheduled-task panel", () => {
   test("opens from the rail and lists what is scheduled", async ({ page }) => {
@@ -47,6 +53,7 @@ test.describe("the scheduled-task panel", () => {
     // The panel is a surface, not an overlay: the transcript is gone while it is open.
     await expect(page.locator('[data-webui-component="composer"]')).toHaveCount(0);
 
+    await waitForLocalImages(page);
     await expect(panel).toHaveScreenshot("scheduling-panel.png", screenshotOptions);
 
     // Closing returns to the conversation, and the panel's own control is what does it — the rail
@@ -92,6 +99,7 @@ test.describe("the scheduled-task panel", () => {
     await page.locator('[data-webui-model-list-row="fixture/stub-model/"]').click();
     await expect(modelField).toContainText("Stub Model");
     await editor.locator('[data-webui-scheduling-field="prompt"]').fill("Summarize the day.");
+    await waitForLocalImages(page);
     await expect(editor).toHaveScreenshot("scheduling-editor.png", screenshotOptions);
     // The editor's submit control is the dialog footer's, so it is not inside the
     // editor's own element.
@@ -160,6 +168,7 @@ test.describe("the scheduled-task panel", () => {
       runs.locator('[data-webui-scheduling-run-session="A"]').first(),
     ).toContainText("打开会话");
 
+    await waitForLocalImages(page);
     await expect(panel).toHaveScreenshot("scheduling-panel-runs.png", screenshotOptions);
 
     // Opening the session a run produced leaves the panel and lands on that session.
diff --git a/packages/webui/test/browser/visual-baselines.spec.mjs b/packages/webui/test/browser/visual-baselines.spec.mjs
index fff9dac6..32ee4046 100644
--- a/packages/webui/test/browser/visual-baselines.spec.mjs
+++ b/packages/webui/test/browser/visual-baselines.spec.mjs
@@ -4,13 +4,14 @@
 import { expect } from "@playwright/test";
 
 import {
+  openApp,
+  screenshotOptions,
+  test,
+  waitForLocalImages,
   assistantBody,
   emitAgentMessage,
   emitStream,
-  openApp,
-  screenshotOptions,
   startTurn,
-  test,
 } from "./harness.mjs";
 
 /**
@@ -54,9 +55,7 @@ test("shell and session rail layout baseline", async ({ page }) => {
   await expect(rail).toBeVisible();
   await expect(rail.getByText("Synthetic session A")).toBeVisible();
   await expect(rail.getByText("Synthetic session B")).toBeVisible();
-  await expect.poll(() => page.locator('img[src^="/assets/"]').evaluateAll((images) =>
-    images.every((image) => image instanceof HTMLImageElement && image.complete && image.naturalWidth > 0),
-  )).toBe(true);
+  await waitForLocalImages(page);
   await expect(shell).toHaveScreenshot("shell-and-rail.png", screenshotOptions);
 });
 
@@ -104,6 +103,7 @@ test("transcript and composer layout baseline", async ({ page }) => {
   const transcript = page.locator('[data-webui-transcript="A"]');
   await assertInViewport(transcript, page);
   await expect(page.getByPlaceholder("输入消息…（输入 / 唤起命令）")).toBeVisible();
+  await waitForLocalImages(page);
   await expect(page.locator("#webui-root")).toHaveScreenshot("transcript-and-composer.png", screenshotOptions);
 });
 
@@ -120,6 +120,7 @@ test("settings dialog layout baseline", async ({ page }) => {
   // same wait the browser panel case uses, over the whole subtree, so this
   // records the settled frame rather than a lucky one.
   await settleAnimations(dialog);
+  await waitForLocalImages(page);
   await expect(dialog).toHaveScreenshot("settings-dialog.png", screenshotOptions);
 });
 
@@ -145,6 +146,7 @@ test("progress panel layout baseline", async ({ page }) => {
   const panel = page.getByTestId("progress-overview-panel");
   await expect(panel).toContainText("Synthetic visual todo");
   await assertInViewport(panel, page);
+  await waitForLocalImages(page);
   await expect(panel).toHaveScreenshot("progress-panel.png", screenshotOptions);
 });
 
@@ -159,6 +161,7 @@ test("embedded browser panel layout baseline", async ({ page }) => {
   });
   await assertInViewport(panel, page);
   await expect(page.getByTestId("workspace-launcher")).toBeVisible();
+  await waitForLocalImages(page);
   await expect(panel).toHaveScreenshot("embedded-browser-panel.png", screenshotOptions);
 });
 
@@ -171,6 +174,7 @@ test("composer command overlay layout baseline", async ({ page }) => {
   const overlay = page.locator('[data-webui-command-menu="true"]');
   await expect(overlay).toBeVisible();
   await assertInViewport(overlay, page);
+  await waitForLocalImages(page);
   await expect(overlay).toHaveScreenshot("composer-command-overlay.png", screenshotOptions);
 });
 
@@ -205,11 +209,13 @@ test("plugin marketplace and skills catalogue layout baselines", async ({ page }
   const grid = await pluginGrid.first().evaluate((node) => getComputedStyle(node).gridTemplateColumns.split(" ").length);
   expect(grid).toBe(2);
   await assertInViewport(pluginGrid.first(), page);
+  await waitForLocalImages(page);
   await expect(surface).toHaveScreenshot("plugin-marketplace.png", screenshotOptions);
 
   await surface.getByRole("button", { name: "技能", exact: true }).click();
   await expect(surface.locator(".webui-plugin-grid .webui-plugin-row")).toHaveCount(2);
   await expect(surface.getByText("Release notes")).toBeVisible();
+  await waitForLocalImages(page);
   await expect(surface).toHaveScreenshot("skill-marketplace.png", screenshotOptions);
 });
 
@@ -240,6 +246,7 @@ test("plugin management skill and MCP rows layout baselines", async ({ page }) =
   await expect(surface.getByText("Local checklist")).toBeVisible();
   await expect(surface.getByLabel("启用 disabled-review")).toBeVisible();
   await assertInViewport(surface.locator(".webui-plugin-list"), page);
+  await waitForLocalImages(page);
   await expect(surface).toHaveScreenshot("skill-management.png", screenshotOptions);
 
   await surface.locator('.webui-plugin-category-filter button', { hasText: "MCP" }).click();
@@ -247,5 +254,6 @@ test("plugin management skill and MCP rows layout baselines", async ({ page }) =
   // removed with the row redesign, so the baseline shows the rows and their actions.
   await expect(surface.getByText("local-http")).toBeVisible();
   await expect(surface.getByText("missing-binary")).toBeVisible();
+  await waitForLocalImages(page);
   await expect(surface).toHaveScreenshot("mcp-management.png", screenshotOptions);
 });
diff --git a/packages/webui/test/integration/agent-transcript.test.ts b/packages/webui/test/integration/agent-transcript.test.ts
index bcbd9833..2469a187 100644
--- a/packages/webui/test/integration/agent-transcript.test.ts
+++ b/packages/webui/test/integration/agent-transcript.test.ts
@@ -1063,7 +1063,25 @@ it.each(["transcript", "cross-client", "external-active-mutation", "external-act
     await page.getByTestId("workspace-launcher-url").fill(pageUrl);
     await page.getByTestId("workspace-launcher-url-submit").click();
     const browserFrame = page.getByTestId("browser-panel-frame");
-    await browserExpect(browserFrame).toBeVisible({ timeout: 30_000 });
+    // The panel can only render a frame after the isolated Chromium has
+    // booted, opened the page and streamed its first picture back over the
+    // event channel. That whole pipeline -- not the product's own
+    // responsiveness -- is what this wait covers, and on a loaded CI runner
+    // it can outlast the 30s window this test used to give it. Give the wait
+    // its own budget, and keep the failure readable: if the panel still
+    // shows its empty placeholder the frame never arrived, and if a
+    // capability notice is on screen the host could not serve a browser at
+    // all. Those are different faults and deserve different fixes.
+    try {
+      await browserExpect(browserFrame).toBeVisible({ timeout: 60_000 });
+    } catch (error) {
+      throw new Error(`${error instanceof Error ? error.message : String(error)}\n${JSON.stringify({
+        emptyFrameStillShowing: await page.getByTestId("browser-panel-frame-empty").count(),
+        capabilityNotices: await page.locator(
+          '[data-testid="browser-panel-unknown"], [data-testid="browser-panel-unauthorized"]',
+        ).allTextContents(),
+      })}`);
+    }
     const browserGeometry = await browserFrame.evaluate((node) => {
       const frame = node.getBoundingClientRect();
       const panel = node.closest(".webui-browser-panel")?.getBoundingClientRect();