diff --git a/src/io/outlookMail.test.ts b/src/io/outlookMail.test.ts
index 5e2aeff..b42cc24 100644
--- a/src/io/outlookMail.test.ts
+++ b/src/io/outlookMail.test.ts
@@ -457,6 +457,50 @@ describe("outlookMail helpers", () => {
     expect(extractMessageHtmlBody(parsed.headers, parsed.body)).toBe("<p><strong>HTML text</strong></p>");
   });
 
+  it("exports inline data images as CID references in related EML", () => {
+    const imageBase64 = "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP8/x8AAwMCAO+/p9sAAAAASUVORK5CYII=";
+    const message: MailMessage = {
+      id: "inline-image",
+      folder: "sent",
+      from: "sender@example.com",
+      to: "reader@example.com",
+      subject: "Inline image",
+      body: "Logo",
+      bodyHtml: `<p>Logo</p><img alt="logo" src="data:image/png;base64,${imageBase64}">`,
+      time: "Mon, 01 Jan 2024 10:00:00 +0000",
+      read: true,
+      flagged: false,
+      attachments: [
+        {
+          id: "logo",
+          fileName: "logo.png",
+          contentType: "image/png",
+          size: 68,
+          contentBase64: imageBase64,
+          disposition: "inline",
+          contentId: "logo@example.com"
+        }
+      ]
+    };
+
+    const eml = buildEmlSource(message);
+    const parsed = parseEmlSource(eml);
+    const attachments = extractMessageAttachments(parsed.headers, parsed.body);
+
+    expect(eml).toContain("Content-Type: multipart/related");
+    expect(eml).toContain("Content-ID: <logo@example.com>");
+    expect(eml).toContain('Content-Disposition: inline; filename="logo.png"');
+    expect(extractMessageHtmlBody(parsed.headers, parsed.body)).toBe('<p>Logo</p><img alt="logo" src="cid:logo@example.com">');
+    expect(extractMessageHtmlBody(parsed.headers, parsed.body)).not.toContain("data:image/png;base64");
+    expect(attachments[0]).toMatchObject({
+      fileName: "logo.png",
+      contentType: "image/png",
+      contentBase64: imageBase64,
+      disposition: "inline",
+      contentId: "logo@example.com"
+    });
+  });
+
   it("собирает multipart/mixed EML с вложениями и RFC 2231 filename", () => {
     const message: MailMessage = {
       id: "1",
diff --git a/src/io/outlookMail.ts b/src/io/outlookMail.ts
index d94dd3f..249442a 100644
--- a/src/io/outlookMail.ts
+++ b/src/io/outlookMail.ts
@@ -298,6 +298,46 @@ export function htmlWithEmbeddedCidAttachments(html: string, attachments: MailAt
   });
 }
 
+function htmlWithCidReferencesForInlineAttachments(html: string, attachments: MailAttachment[] = []): string {
+  if (!html.trim() || attachments.length === 0) {
+    return html;
+  }
+
+  const contentIdsByDataUri = new Map<string, string>();
+  attachments.forEach((attachment) => {
+    const contentId = cleanContentId(attachment.contentId);
+    const contentType = sanitizeMimeType(attachment.contentType);
+    const contentBase64 = attachment.contentBase64.trim();
+    if (!contentId || attachment.disposition !== "inline" || !contentBase64 || !isEmbeddableCidImageContentType(contentType)) {
+      return;
+    }
+
+    const key = cidImageDataUriKey(contentType, contentBase64);
+    if (!contentIdsByDataUri.has(key)) {
+      contentIdsByDataUri.set(key, contentId);
+    }
+  });
+
+  if (contentIdsByDataUri.size === 0) {
+    return html;
+  }
+
+  return html.replace(
+    /\bsrc\s*=\s*(?:(["'])\s*data:(image\/(?:png|jpe?g|gif|bmp|webp));base64,([^"'>\s]+)\1|data:(image\/(?:png|jpe?g|gif|bmp|webp));base64,([^\s"'<>]+))/gi,
+    (match, quote: string | undefined, quotedType: string | undefined, quotedBase64: string | undefined, unquotedType: string | undefined, unquotedBase64: string | undefined) => {
+      const contentType = quotedType ?? unquotedType ?? "";
+      const contentBase64 = (quotedBase64 ?? unquotedBase64 ?? "").trim();
+      const contentId = contentIdsByDataUri.get(cidImageDataUriKey(contentType, contentBase64));
+      if (!contentId) {
+        return match;
+      }
+
+      const cidReference = escapeHtmlAttribute(`cid:${contentId}`);
+      return quote ? `src=${quote}${cidReference}${quote}` : `src="${cidReference}"`;
+    }
+  );
+}
+
 export async function createMailAttachmentFromFile(file: File): Promise<MailAttachment> {
   return {
     id: createAttachmentId(file.name),
@@ -499,6 +539,28 @@ export function buildEmlSource(message: MailMessage): string {
   if (attachments.length > 0) {
     const boundary = createMultipartBoundary(message);
     const alternativeBoundary = createAlternativeBoundary(message);
+    const inlineRelatedAttachments = hasHtmlBody ? attachments.filter(isInlineRelatedAttachment) : [];
+    const mixedAttachments = inlineRelatedAttachments.length > 0 ? attachments.filter((attachment) => !isInlineRelatedAttachment(attachment)) : attachments;
+    if (hasHtmlBody && inlineRelatedAttachments.length > 0 && mixedAttachments.length === 0) {
+      const relatedBoundary = createRelatedBoundary(message);
+      const lines = [
+        `From: ${sanitizeHeaderValue(message.from)}`,
+        `To: ${sanitizeHeaderValue(message.to)}`,
+        ...optionalAddressHeaders(message),
+        `Subject: ${encodeHeaderValue(message.subject || "Без темы")}`,
+        `Date: ${sanitizeHeaderValue(message.time || new Date().toUTCString())}`,
+        ...optionalThreadHeaders(message),
+        ...optionalPriorityHeaders(message),
+        "MIME-Version: 1.0",
+        `Content-Type: multipart/related; boundary="${relatedBoundary}"`,
+        "",
+        ...buildRelatedBodyLines(relatedBoundary, alternativeBoundary, message, inlineRelatedAttachments),
+        ""
+      ];
+
+      return lines.join("\r\n");
+    }
+
     const lines = [
       `From: ${sanitizeHeaderValue(message.from)}`,
       `To: ${sanitizeHeaderValue(message.to)}`,
@@ -511,8 +573,12 @@ export function buildEmlSource(message: MailMessage): string {
       `Content-Type: multipart/mixed; boundary="${boundary}"`,
       "",
       `--${boundary}`,
-      ...(hasHtmlBody ? buildAlternativePartLines(alternativeBoundary, message) : buildPlainTextPartLines(message)),
-      ...attachments.flatMap((attachment) => buildAttachmentPartLines(boundary, attachment)),
+      ...(inlineRelatedAttachments.length > 0
+        ? buildRelatedPartLines(createRelatedBoundary(message), alternativeBoundary, message, inlineRelatedAttachments)
+        : hasHtmlBody
+          ? buildAlternativePartLines(alternativeBoundary, message)
+          : buildPlainTextPartLines(message)),
+      ...mixedAttachments.flatMap((attachment) => buildAttachmentPartLines(boundary, attachment)),
       `--${boundary}--`,
       ""
     ];
@@ -567,7 +633,12 @@ function buildPlainTextPartLines(message: MailMessage): string[] {
 }
 
 function buildHtmlPartLines(message: MailMessage): string[] {
-  return ["Content-Type: text/html; charset=utf-8", "Content-Transfer-Encoding: 8bit", "", normalizeMailNewlines(message.bodyHtml || "")];
+  return [
+    "Content-Type: text/html; charset=utf-8",
+    "Content-Transfer-Encoding: 8bit",
+    "",
+    normalizeMailNewlines(htmlWithCidReferencesForInlineAttachments(message.bodyHtml || "", message.attachments ?? []))
+  ];
 }
 
 function buildAlternativePartLines(boundary: string, message: MailMessage): string[] {
@@ -582,6 +653,18 @@ function buildAlternativePartLines(boundary: string, message: MailMessage): stri
   ];
 }
 
+function buildRelatedPartLines(boundary: string, alternativeBoundary: string, message: MailMessage, inlineAttachments: MailAttachment[]): string[] {
+  return [`Content-Type: multipart/related; boundary="${boundary}"`, "", ...buildRelatedBodyLines(boundary, alternativeBoundary, message, inlineAttachments)];
+}
+
+function buildRelatedBodyLines(boundary: string, alternativeBoundary: string, message: MailMessage, inlineAttachments: MailAttachment[]): string[] {
+  return [`--${boundary}`, ...buildAlternativePartLines(alternativeBoundary, message), ...inlineAttachments.flatMap((attachment) => buildAttachmentPartLines(boundary, attachment)), `--${boundary}--`];
+}
+
+function isInlineRelatedAttachment(attachment: MailAttachment): boolean {
+  return attachment.disposition === "inline" && Boolean(cleanContentId(attachment.contentId));
+}
+
 function optionalAddressHeaders(message: MailMessage): string[] {
   return [
     ...(message.cc?.trim() ? [`Cc: ${sanitizeHeaderValue(message.cc)}`] : []),
@@ -784,6 +867,10 @@ function createAlternativeBoundary(message: MailMessage): string {
   return `${createMultipartBoundary(message)}-alternative`;
 }
 
+function createRelatedBoundary(message: MailMessage): string {
+  return `${createMultipartBoundary(message)}-related`;
+}
+
 function buildAttachmentPartLines(boundary: string, attachment: MailAttachment): string[] {
   const safeContentType = sanitizeMimeType(attachment.contentType);
   const disposition = attachment.disposition === "inline" ? "inline" : "attachment";
@@ -820,11 +907,24 @@ function sanitizeMimeType(value = "application/octet-stream"): string {
 }
 
 function isEmbeddableCidImageContentType(value: string): boolean {
-  return ["image/png", "image/jpeg", "image/jpg", "image/gif", "image/bmp", "image/webp"].includes(value.toLowerCase());
+  return ["image/png", "image/jpeg", "image/gif", "image/bmp", "image/webp"].includes(normalizedCidImageContentType(value));
+}
+
+function normalizedCidImageContentType(value: string): string {
+  const contentType = value.toLowerCase();
+  return contentType === "image/jpg" ? "image/jpeg" : contentType;
+}
+
+function cidImageDataUriKey(contentType: string, contentBase64: string): string {
+  return `${normalizedCidImageContentType(contentType)}:${contentBase64.trim()}`;
+}
+
+function cleanContentId(value = ""): string {
+  return value.trim().replace(/^<|>$/g, "");
 }
 
 function normalizedContentId(value = ""): string {
-  return value.trim().replace(/^<|>$/g, "").toLowerCase();
+  return cleanContentId(value).toLowerCase();
 }
 
 function decodeUriComponentSafe(value: string): string {
@@ -835,6 +935,15 @@ function decodeUriComponentSafe(value: string): string {
   }
 }
 
+function escapeHtmlAttribute(value: string): string {
+  return value
+    .replace(/&/g, "&amp;")
+    .replace(/"/g, "&quot;")
+    .replace(/'/g, "&#39;")
+    .replace(/</g, "&lt;")
+    .replace(/>/g, "&gt;");
+}
+
 function wrapBase64(value: string): string {
   return (value.match(/.{1,76}/g) ?? [""]).join("\r\n");
 }