diff --git a/server/api/controllers/file-attachments/download-thumbnail.js b/server/api/controllers/file-attachments/download-thumbnail.js
index 077bb873..7ea2866e 100644
--- a/server/api/controllers/file-attachments/download-thumbnail.js
+++ b/server/api/controllers/file-attachments/download-thumbnail.js
@@ -86,7 +86,7 @@ module.exports = {
     }
 
     this.res.type(attachment.data.mimeType);
-    this.res.set('Cache-Control', 'private, max-age=900'); // TODO: move to config
+    this.res.set('Cache-Control', 'private, max-age=86400, no-transform'); // TODO: move to config
 
     return exits.success(readStream);
   },
diff --git a/server/api/controllers/file-attachments/download.js b/server/api/controllers/file-attachments/download.js
index 8419bceb..70442294 100644
--- a/server/api/controllers/file-attachments/download.js
+++ b/server/api/controllers/file-attachments/download.js
@@ -84,7 +84,7 @@ module.exports = {
     if (!INLINE_MIME_TYPES_SET.has(attachment.data.mimeType) && !attachment.data.image) {
       this.res.set('Content-Disposition', 'attachment');
     }
-    this.res.set('Cache-Control', 'private, max-age=900'); // TODO: move to config
+    this.res.set('Cache-Control', 'private, max-age=86400, no-transform'); // TODO: move to config
 
     return exits.success(readStream);
   },