diff --git a/lib/config.js b/lib/config.js
index 99b9427..a906dfa 100644
--- a/lib/config.js
+++ b/lib/config.js
@@ -57,15 +57,15 @@ var heartbeattimeout = config.heartbeattimeout || 10000;
 var documentmaxlength = config.documentmaxlength || 100000;
 
 // image upload setting, available options are imgur/s3/filesystem
-var imageUploadType = config.imageUploadType || 'imgur';
+var imageUploadType = process.env.HMD_IMAGE_UPLOAD_TYPE || config.imageUploadType || 'imgur';
 
 config.s3 = config.s3 || {};
 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
+    accessKeyId: process.env.HMD_S3_ACCESS_KEY_ID || config.s3.accessKeyId,
+    secretAccessKey: process.env.HMD_S3_SECRET_ACCESS_KEY || config.s3.secretAccessKey,
+    region: process.env.HMD_S3_REGION || config.s3.region
 }
-var s3bucket = process.env.S3_BUCKET || config.s3.bucket;
+var s3bucket = process.env.HMD_S3_BUCKET || config.s3.bucket;
 
 // auth
 var facebook = (process.env.HMD_FACEBOOK_CLIENTID && process.env.HMD_FACEBOOK_CLIENTSECRET) ? {