diff --git a/lib/config.js b/lib/config.js
index ecc68f7..99b9427 100644
--- a/lib/config.js
+++ b/lib/config.js
@@ -59,14 +59,13 @@ var documentmaxlength = config.documentmaxlength || 100000;
 // image upload setting, available options are imgur/s3/filesystem
 var imageUploadType = config.imageUploadType || 'imgur';
 
-var s3Keys = ['accessKeyId', 'secretAccessKey', 'region'];
 config.s3 = config.s3 || {};
-var s3 = s3Keys.reduce(function(prev, cur) {
-    prev[cur] = config.s3[cur];
-    return prev;
-}, {});
-
-var s3bucket = config.s3.bucket;
+var s3 = {
+    accessKeyId: process.env.S3_ACCESS_KEY_ID || config.s3.accessKeyId,
+    secretAccessKey: process.env.S3_SECRET_ACCESS_KEY || config.s3.secretAccessKey,
+    region: process.env.S3_REGION || config.s3.region
+}
+var s3bucket = process.env.S3_BUCKET || config.s3.bucket;
 
 // auth
 var facebook = (process.env.HMD_FACEBOOK_CLIENTID && process.env.HMD_FACEBOOK_CLIENTSECRET) ? {