diff --git a/packages/server/src/server/agent/providers/claude/agent.image-rendering.test.ts b/packages/server/src/server/agent/providers/claude/agent.image-rendering.test.ts
index 66891e01bf..5a06fea7fd 100644
--- a/packages/server/src/server/agent/providers/claude/agent.image-rendering.test.ts
+++ b/packages/server/src/server/agent/providers/claude/agent.image-rendering.test.ts
@@ -140,11 +140,11 @@ function imageMessages(items: AgentTimelineItem[]): string[] {
   return items
     .filter((item) => item.type === "assistant_message")
     .map((item) => (item as { text: string }).text)
-    .filter((text) => text.startsWith("!["));
+    .filter((text) => text.trimStart().startsWith("!["));
 }
 
 function markdownImageSource(markdown: string): string {
-  const match = markdown.match(/^!\[[^\]]*]\((.*)\)$/);
+  const match = markdown.trim().match(/^!\[[^\]]*]\((.*)\)$/);
   if (!match) {
     throw new Error(`Expected markdown image, got: ${markdown}`);
   }
diff --git a/packages/server/src/server/agent/providers/codex-app-server-agent.test.ts b/packages/server/src/server/agent/providers/codex-app-server-agent.test.ts
index c8269722a7..8238a80131 100644
--- a/packages/server/src/server/agent/providers/codex-app-server-agent.test.ts
+++ b/packages/server/src/server/agent/providers/codex-app-server-agent.test.ts
@@ -502,7 +502,7 @@ function asInternals(session: CodexTestSession): CodexSessionTestAccess {
 }
 
 function markdownImageSource(markdown: string): string {
-  const match = markdown.match(/^!\[[^\]]*]\((.*)\)$/);
+  const match = markdown.trim().match(/^!\[[^\]]*]\((.*)\)$/);
   if (!match) {
     throw new Error(`Expected markdown image, got: ${markdown}`);
   }
@@ -6000,7 +6000,7 @@ describe("Codex app-server provider", () => {
         turnId: "test-turn",
         item: {
           type: "assistant_message",
-          text: "![Image](file:///tmp/paseo%20image.png)",
+          text: "\n\n![Image](file:///tmp/paseo%20image.png)\n\n",
         },
       },
     ]);
@@ -6032,7 +6032,7 @@ describe("Codex app-server provider", () => {
           turnId: "test-turn",
           item: {
             type: "assistant_message",
-            text: `![Image](${expectedPath})`,
+            text: `\n\n![Image](${expectedPath})\n\n`,
           },
         },
       ]);
diff --git a/packages/server/src/server/agent/providers/opencode/v2/timeline.test.ts b/packages/server/src/server/agent/providers/opencode/v2/timeline.test.ts
index 82236de2b8..d86b9a7dcb 100644
--- a/packages/server/src/server/agent/providers/opencode/v2/timeline.test.ts
+++ b/packages/server/src/server/agent/providers/opencode/v2/timeline.test.ts
@@ -92,7 +92,7 @@ test("a tool's image output is shown as an image, not as base64 in the tool outp
     },
     {
       type: "assistant_message",
-      text: expect.stringMatching(/^!\[Image\]\(file:\/\/.*paseo-attachments.*\.png\)$/),
+      text: expect.stringMatching(/^\n\n!\[Image\]\(file:\/\/.*paseo-attachments.*\.png\)\n\n$/),
     },
   ]);
   expect(timeline.messages([screenshot])).toEqual([]);
diff --git a/packages/server/src/server/agent/providers/provider-image-output.test.ts b/packages/server/src/server/agent/providers/provider-image-output.test.ts
index 0c32af04fe..b4f4784a66 100644
--- a/packages/server/src/server/agent/providers/provider-image-output.test.ts
+++ b/packages/server/src/server/agent/providers/provider-image-output.test.ts
@@ -1,5 +1,7 @@
 import { existsSync, rmSync } from "node:fs";
 import path from "node:path";
+import MarkdownIt from "markdown-it";
+import { projectTimelineRows } from "../timeline-projection.js";
 import { describe, expect, test } from "vitest";
 
 import {
@@ -44,7 +46,7 @@ describe("isProviderImageMarkdown", () => {
     );
 
     expect(markdown).toBe(
-      `![Image](file:///C:/Users/me/AppData/Local/Temp/paseo-attachments/${HASH}.png)`,
+      `\n\n![Image](file:///C:/Users/me/AppData/Local/Temp/paseo-attachments/${HASH}.png)\n\n`,
     );
     expect(isProviderImageMarkdown(markdown)).toBe(true);
   });
@@ -53,20 +55,20 @@ describe("isProviderImageMarkdown", () => {
     const markdown = renderImageMarkdown("/home/user/Projects/Project With Spaces/screenshot.png");
 
     expect(markdown).toBe(
-      "![Image](file:///home/user/Projects/Project%20With%20Spaces/screenshot.png)",
+      "\n\n![Image](file:///home/user/Projects/Project%20With%20Spaces/screenshot.png)\n\n",
     );
   });
 
   test("encodes URI-significant characters in POSIX file paths", () => {
     const markdown = renderImageMarkdown("/tmp/screenshot#1?draft.png");
 
-    expect(markdown).toBe("![Image](file:///tmp/screenshot%231%3Fdraft.png)");
+    expect(markdown).toBe("\n\n![Image](file:///tmp/screenshot%231%3Fdraft.png)\n\n");
   });
 
   test("preserves double-leading slashes in POSIX file paths", () => {
     const markdown = renderImageMarkdown("//tmp/screenshot#1.png");
 
-    expect(markdown).toBe("![Image](file:////tmp/screenshot%231.png)");
+    expect(markdown).toBe("\n\n![Image](file:////tmp/screenshot%231.png)\n\n");
   });
 
   test.each([
@@ -77,7 +79,7 @@ describe("isProviderImageMarkdown", () => {
       "file://server/share/shot%3Fdraft.png",
     ],
   ])("encodes %s image paths as file URIs", (_label, imagePath, expectedSource) => {
-    expect(renderImageMarkdown(imagePath)).toBe(`![Image](${expectedSource})`);
+    expect(renderImageMarkdown(imagePath)).toBe(`\n\n![Image](${expectedSource})\n\n`);
   });
 
   test("rejects user-authored markdown that is not a materialized attachment", () => {
@@ -113,3 +115,52 @@ describe("materializeProviderImage", () => {
     }
   });
 });
+
+describe("provider image paragraph boundaries", () => {
+  test.each(["", "\n"])("keeps image outputs separate from prose ending in %j", (ending) => {
+    const image = renderProviderImageOutputAsAssistantMarkdown({
+      url: "https://example.com/chart.png",
+    });
+    if (!image) throw new Error("Expected image output");
+    const projected = projectTimelineRows({
+      mode: "projected",
+      rows: [
+        {
+          seq: 1,
+          timestamp: "2026-10-16T15:08:23Z",
+          item: { type: "assistant_message", text: `Before${ending}`, messageId: "commentary" },
+        },
+        { seq: 2, timestamp: "2026-10-16T15:08:24Z", item: image },
+        {
+          seq: 3,
+          timestamp: "2026-10-16T15:08:25Z",
+          item: { type: "assistant_message", text: "After" },
+        },
+      ],
+    });
+    expect(projected).toHaveLength(1);
+    const item = projected[0]!.item;
+    if (item.type !== "assistant_message") throw new Error("Expected assistant message");
+    const paragraphs = new MarkdownIt()
+      .parse(item.text, {})
+      .filter((token) => token.type === "inline");
+    expect(paragraphs.map((token) => token.content)).toEqual([
+      "Before",
+      "![Image](https://example.com/chart.png)",
+      "After",
+    ]);
+  });
+});
+
+test("materialized image output retains paragraph boundaries and attachment recognition", () => {
+  const item = renderProviderImageOutputAsAssistantMarkdown(
+    { data: "YWJjMTIz", mimeType: "image/png" },
+    { materialize: () => ({ path: `/tmp/paseo-attachments/${HASH}.png` }) },
+  );
+  expect(item).toEqual({
+    type: "assistant_message",
+    text: `\n\n![Image](file:///tmp/paseo-attachments/${HASH}.png)\n\n`,
+  });
+  if (!item || item.type !== "assistant_message") throw new Error("Expected image output");
+  expect(isProviderImageMarkdown(item.text)).toBe(true);
+});
diff --git a/packages/server/src/server/agent/providers/provider-image-output.ts b/packages/server/src/server/agent/providers/provider-image-output.ts
index 387158b32f..ba8843918b 100644
--- a/packages/server/src/server/agent/providers/provider-image-output.ts
+++ b/packages/server/src/server/agent/providers/provider-image-output.ts
@@ -108,7 +108,7 @@ const PROVIDER_IMAGE_MARKDOWN = new RegExp(
 );
 
 export function isProviderImageMarkdown(text: string): boolean {
-  return PROVIDER_IMAGE_MARKDOWN.test(text);
+  return PROVIDER_IMAGE_MARKDOWN.test(text.trimStart());
 }
 
 interface RenderProviderImageOutputOptions {
@@ -178,7 +178,8 @@ export function renderProviderImageOutputAsAssistantMarkdown(
     const altText = escapeMarkdownImageAlt(nonEmptyString(image.altText) ?? "Image");
     return {
       type: "assistant_message",
-      text: `![${altText}](${escapeMarkdownImageSource(source)})`,
+      // Image outputs remain standalone paragraphs when adjacent assistant chunks merge.
+      text: `\n\n![${altText}](${escapeMarkdownImageSource(source)})\n\n`,
     };
   }
 
@@ -208,6 +209,6 @@ export function renderProviderImageOutputAsAssistantMarkdown(
   const altText = escapeMarkdownImageAlt(nonEmptyString(image.altText) ?? "Image");
   return {
     type: "assistant_message",
-    text: `![${altText}](${escapeMarkdownImageSource(materialized.path)})`,
+    text: `\n\n![${altText}](${escapeMarkdownImageSource(materialized.path)})\n\n`,
   };
 }