diff --git a/src/routes/api/files.js b/src/routes/api/files.js
index 54ba741fb..88c18354d 100644
--- a/src/routes/api/files.js
+++ b/src/routes/api/files.js
@@ -1,6 +1,5 @@
 "use strict";
 
-const noteService = require('../../services/notes');
 const protectedSessionService = require('../../services/protected_session');
 const repository = require('../../services/repository');
 const utils = require('../../services/utils');
@@ -45,7 +44,9 @@ async function downloadNoteFile(noteId, res, contentDisposition = true) {
     if (contentDisposition) {
         // (one) reason we're not using the originFileName (available as label) is that it's not
         // available for older note revisions and thus would be inconsistent
-        res.setHeader('Content-Disposition', utils.getContentDisposition(note.title || "untitled"));
+        const filename = utils.formatDownloadTitle(note.title, note.type, note.mime);
+
+        res.setHeader('Content-Disposition', utils.getContentDisposition(filename));
     }
 
     res.setHeader('Content-Type', note.mime);
@@ -70,4 +71,4 @@ module.exports = {
     openFile,
     downloadFile,
     downloadNoteFile
-};
\ No newline at end of file
+};
diff --git a/src/routes/api/note_revisions.js b/src/routes/api/note_revisions.js
index 023ba30ee..7f325f725 100644
--- a/src/routes/api/note_revisions.js
+++ b/src/routes/api/note_revisions.js
@@ -38,13 +38,7 @@ async function getNoteRevision(req) {
  * @return {string}
  */
 function getRevisionFilename(noteRevision) {
-    let filename = noteRevision.title || "untitled";
-
-    if (noteRevision.type === 'text') {
-        filename += '.html';
-    } else if (['relation-map', 'search'].includes(noteRevision.type)) {
-        filename += '.json';
-    }
+    let filename = utils.formatDownloadTitle(noteRevision.title, noteRevision.type, noteRevision.mime);
 
     const extension = path.extname(filename);
     const date = noteRevision.dateCreated
@@ -158,4 +152,4 @@ module.exports = {
     eraseAllNoteRevisions,
     eraseNoteRevision,
     restoreNoteRevision
-};
\ No newline at end of file
+};
diff --git a/src/services/notes.js b/src/services/notes.js
index 152c72ec4..a04164ef5 100644
--- a/src/services/notes.js
+++ b/src/services/notes.js
@@ -13,6 +13,7 @@ const Attribute = require('../entities/attribute');
 const hoistedNoteService = require('../services/hoisted_note');
 const protectedSessionService = require('../services/protected_session');
 const log = require('../services/log');
+const utils = require('../services/utils');
 const noteRevisionService = require('../services/note_revisions');
 const attributeService = require('../services/attributes');
 const request = require('./request');
@@ -276,9 +277,9 @@ async function downloadImage(noteId, imageUrl) {
 const downloadImagePromises = {};
 
 function replaceUrl(content, url, imageNote) {
-    const quoted = url.replace(/[.*+\-?^${}()|[\]\\]/g, '\\$&');
+    const quotedUrl = utils.quoteRegex(url);
 
-    return content.replace(new RegExp(`\\s+src=[\"']${quoted}[\"']`, "g"), ` src="api/images/${imageNote.noteId}/${imageNote.title}"`);
+    return content.replace(new RegExp(`\\s+src=[\"']${quotedUrl}[\"']`, "g"), ` src="api/images/${imageNote.noteId}/${imageNote.title}"`);
 }
 
 async function downloadImages(noteId, content) {
diff --git a/src/services/utils.js b/src/services/utils.js
index 57af4218e..7cb02ae40 100644
--- a/src/services/utils.js
+++ b/src/services/utils.js
@@ -5,6 +5,7 @@ const randtoken = require('rand-token').generator({source: 'crypto'});
 const unescape = require('unescape');
 const escape = require('escape-html');
 const sanitize = require("sanitize-filename");
+const mimeTypes = require('mime-types');
 
 function newEntityId() {
     return randomString(12);
@@ -166,10 +167,46 @@ function isStringNote(type, mime) {
         || STRING_MIME_TYPES.includes(mime);
 }
 
-function replaceAll(string, replaceWhat, replaceWith) {
-    const escapedWhat = replaceWhat.replace(/([\/,!\\^${}\[\]().*+?|<>\-&])/g, "\\$&");
+function quoteRegex(url) {
+    return url.replace(/[.*+\-?^${}()|[\]\\]/g, '\\$&');
+}
 
-    return string.replace(new RegExp(escapedWhat, "g"), replaceWith);
+function replaceAll(string, replaceWhat, replaceWith) {
+    const quotedReplaceWhat = quoteRegex(replaceWhat);
+
+    return string.replace(new RegExp(quotedReplaceWhat, "g"), replaceWith);
+}
+
+function formatDownloadTitle(filename, type, mime) {
+    if (!filename) {
+        filename = "untitled";
+    }
+
+    if (type === 'text') {
+        return filename + '.html';
+    } else if (['relation-map', 'search'].includes(type)) {
+        return filename + '.json';
+    } else {
+        if (!mime) {
+            return filename;
+        }
+
+        mime = mime.toLowerCase();
+        const filenameLc = filename.toLowerCase();
+        const extensions = mimeTypes.extensions[mime];
+
+        if (!extensions || extensions.length === 0) {
+            return filename;
+        }
+
+        for (const ext of extensions) {
+            if (filenameLc.endsWith('.' + ext)) {
+                return filename;
+            }
+        }
+
+        return filename + '.' + extensions[0];
+    }
 }
 
 module.exports = {
@@ -198,5 +235,7 @@ module.exports = {
     sanitizeFilenameForHeader,
     getContentDisposition,
     isStringNote,
-    replaceAll
-};
\ No newline at end of file
+    quoteRegex,
+    replaceAll,
+    formatDownloadTitle
+};