diff --git a/apps/server/src/services/export/zip.ts b/apps/server/src/services/export/zip.ts
index 1bfc1e842..10b84abce 100644
--- a/apps/server/src/services/export/zip.ts
+++ b/apps/server/src/services/export/zip.ts
@@ -23,6 +23,7 @@ import { AdvancedExportOptions, type ExportFormat, ZipExportProviderData } from
 import MarkdownExportProvider from "./zip/markdown.js";
 import ShareThemeExportProvider from "./zip/share_theme.js";
 import type BNote from "../../becca/entities/bnote.js";
+import { NoteType } from "@triliumnext/commons";
 
 async function exportToZip(taskContext: TaskContext, branch: BBranch, format: ExportFormat, res: Response | fs.WriteStream, setHeaders = true, zipExportOptions?: AdvancedExportOptions) {
     if (!["html", "markdown", "share"].includes(format)) {
@@ -77,7 +78,7 @@ async function exportToZip(taskContext: TaskContext, branch: BBranch, format: Ex
         }
     }
 
-    function getDataFileName(type: string | null, mime: string, baseFileName: string, existingFileNames: Record<string, number>): string {
+    function getDataFileName(type: NoteType | null, mime: string, baseFileName: string, existingFileNames: Record<string, number>): string {
         let fileName = baseFileName.trim();
 
         // Crop fileName to avoid its length exceeding 30 and prevent cutting into the extension.
diff --git a/apps/server/src/services/export/zip/abstract_provider.ts b/apps/server/src/services/export/zip/abstract_provider.ts
index f777ed1cb..c9645a843 100644
--- a/apps/server/src/services/export/zip/abstract_provider.ts
+++ b/apps/server/src/services/export/zip/abstract_provider.ts
@@ -3,6 +3,7 @@ import type { default as NoteMeta, NoteMetaFile } from "../../meta/note_meta.js"
 import type BNote from "../../../becca/entities/bnote.js";
 import type BBranch from "../../../becca/entities/bbranch.js";
 import mimeTypes from "mime-types";
+import { NoteType } from "@triliumnext/commons";
 
 type RewriteLinksFn = (content: string, noteMeta: NoteMeta) => string;
 
@@ -51,7 +52,16 @@ export abstract class ZipExportProvider {
     abstract prepareContent(title: string, content: string | Buffer, noteMeta: NoteMeta, note: BNote | undefined, branch: BBranch): string | Buffer;
     abstract afterDone(rootMeta: NoteMeta): void;
 
-    mapExtension(type: string | null, mime: string, existingExtension: string, format: ExportFormat) {
+    /**
+     * Determines the extension of the resulting file for a specific note type.
+     *
+     * @param type the type of the note.
+     * @param mime the mime type of the note.
+     * @param existingExtension the existing extension, including the leading period character.
+     * @param format the format requested for export (e.g. HTML, Markdown).
+     * @returns an extension *without* the leading period character, or `null` to preserve the existing extension instead.
+     */
+    mapExtension(type: NoteType | null, mime: string, existingExtension: string, format: ExportFormat) {
         // the following two are handled specifically since we always want to have these extensions no matter the automatic detection
         // and/or existing detected extensions in the note name
         if (type === "text" && format === "markdown") {
diff --git a/apps/server/src/services/export/zip/share_theme.ts b/apps/server/src/services/export/zip/share_theme.ts
index 03bdb68b4..06609b031 100644
--- a/apps/server/src/services/export/zip/share_theme.ts
+++ b/apps/server/src/services/export/zip/share_theme.ts
@@ -1,6 +1,6 @@
 import { join } from "path";
 import NoteMeta, { NoteMetaFile } from "../../meta/note_meta";
-import { ZipExportProvider } from "./abstract_provider.js";
+import { ExportFormat, ZipExportProvider } from "./abstract_provider.js";
 import { RESOURCE_DIR } from "../../resource_dir";
 import { getResourceDir, isDev } from "../../utils";
 import fs from "fs";
@@ -65,6 +65,14 @@ export default class ShareThemeExportProvider extends ZipExportProvider {
         this.#saveIndex(rootMeta);
     }
 
+    mapExtension(type: string | null, mime: string, existingExtension: string, format: ExportFormat): string | null {
+        if (mime.startsWith("image/")) {
+            return null;
+        }
+
+        return "html";
+    }
+
     #saveIndex(rootMeta: NoteMeta) {
         if (!this.indexMeta?.dataFileName) {
             return;