diff --git a/bin/jpegoptim.aws b/bin/jpegoptim.aws
new file mode 100755
index 0000000..94eb573
Binary files /dev/null and b/bin/jpegoptim.aws differ
diff --git a/context.json b/context.json
new file mode 100644
index 0000000..9e26dfe
--- /dev/null
+++ b/context.json
@@ -0,0 +1 @@
+{}
\ No newline at end of file
diff --git a/event.json b/event.json
new file mode 100644
index 0000000..c7b0490
--- /dev/null
+++ b/event.json
@@ -0,0 +1,38 @@
+{
+  "Records": [
+    {
+      "eventVersion": "2.0",
+      "eventTime": "1970-01-01T00:00:00.000Z",
+      "requestParameters": {
+        "sourceIPAddress": "127.0.0.1"
+      },
+      "s3": {
+        "configurationId": "testConfigRule",
+        "object": {
+          "eTag": "0123456789abcdef0123456789abcdef",
+          "sequencer": "0A1B2C3D4E5F678901",
+          "key": "foo/bar/3/e/f/e/3efed655ff1a21cb60bba97cd3c2296877fb8a5a.jpg",
+          "size": 1024
+        },
+        "bucket": {
+          "arn": "arn:aws:s3:::bucket",
+          "name": "bucket",
+          "ownerIdentity": {
+            "principalId": "EXAMPLE"
+          }
+        },
+        "s3SchemaVersion": "1.0"
+      },
+      "responseElements": {
+        "x-amz-id-2": "EXAMPLE123/5678abcdefghijklambdaisawesome/mnopqrstuvwxyzABCDEFGH",
+        "x-amz-request-id": "EXAMPLE123456789"
+      },
+      "awsRegion": "eu-central-1",
+      "eventName": "ObjectCreated:Put",
+      "userIdentity": {
+        "principalId": "EXAMPLE"
+      },
+      "eventSource": "aws:s3"
+    }
+  ]
+}
\ No newline at end of file
diff --git a/lib/optim.js b/lib/optim.js
index 3873e4c..ac7d2ff 100644
--- a/lib/optim.js
+++ b/lib/optim.js
@@ -1,7 +1,9 @@
 var aws = require('aws-sdk');
 var s3 = new aws.S3({ apiVersion: '2006-03-01' });
-var Imagemin = require('imagemin');
-var optipng = require('imagemin-optipng');
+var imagemin = require('imagemin');
+var imageminOptipng = require('imagemin-optipng');
+var imageminJpegoptim = require('imagemin-jpegoptim');
+
 var async = require('async');
 
 var acl = process.env.UPLOAD_ACL || 'public-read';
@@ -9,14 +11,14 @@ var uploadBucket = process.env.UPLOAD_BUCKET;
 var pngLevel = +process.env.PNG_OPTIM_LEVEL || 7;
 var skipSize = +process.env.MAX_FILE_SIZE || -1;
 
-exports.optim = function(event, context) {
+exports.optim = function(event, context, callback) {
 
   var bucket = event.Records[0].s3.bucket.name;
   var key = event.Records[0].s3.object.key;
 
-  if(!/\.png$/.test(key)){
-    console.log('Not a PNG');
-    return setImmediate(function(){ context.done(); });
+  if(!/\.png$/.test(key) && !/\.jpg$/.test(key)){
+    console.log('Not a PNG or JPG');
+    return setImmediate(function(){ callback(null, 'Not a PNG'); });
   }
 
   key = require('querystring').parse('a=' + key).a;
@@ -57,39 +59,55 @@ exports.optim = function(event, context) {
     },
 
     function(meta, obj, cb){
-      new Imagemin()
-        .src(obj.Body)
-        .use(optipng({ optimizationLevel: pngLevel }))
-        .run(function(err, files){
-          if(err) return cb(err);
-
-          console.log('Optimized! Final file size is ' + files[0].contents.length + ' bytes');
+        var plugin
+        if(/\.png$/.test(key)){
+           plugin = imageminOptipng({optimizationLevel: pngLevel});
+        } else {
+          plugin = imageminJpegoptim({progressive: true});
+        }
 
-          cb(null, meta, obj, files[0])
+        imagemin.buffer(obj.Body, {use: [plugin]}).then(buf => {
+            console.log('Optimized! Final file size is ' + buf.length + ' bytes');
+            cb(null, meta, obj, buf)
+        }).catch(err => {
+            callback(err)
         });
     },
 
-    function(meta, obj, file, cb){
-      meta.Metadata.optimized = 'yes';
-
-      s3.putObject({
-        ACL: acl,
-        Bucket: uploadBucket || bucket,
-        Key: key,
-        Body: file.contents,
-        ContentType: obj.ContentType,
-        Metadata: meta.Metadata
-      }, function(err){
-        if(err) return cb(err);
-
-        console.log('done!');
-        cb();
-      });
+    function(meta, obj, body, cb){
+      var oriSize = obj.Body.length
+      var newSize = body.length
+      var percent = Math.round(((oriSize - newSize) / oriSize) * 10000) / 100;
+      console.log('File ' + key + ' was optimzed from ' + oriSize + ' bytes to ' + newSize + ' bytes. ' + percent + '%.')
+
+      if (newSize < oriSize) {
+        meta.Metadata.optimized = 'yes';
+
+        s3.putObject({
+          ACL: acl,
+          Bucket: uploadBucket || bucket,
+          Key: key,
+          Body: body,
+          ContentType: obj.ContentType,
+          Metadata: meta.Metadata,
+          StorageClass: meta.StorageClass
+        }, function (err) {
+          if (err) return cb(err);
+
+          console.log('done!');
+          callback(null, 'File was optimzed from ' + oriSize + ' bytes to ' + newSize + ' bytes. ' + percent + '%.')
+        });
+      } else {
+        console.log("Optimized file was not smaller than original file. Not uploading.")
+        callback(null, "Optimized file was not smaller than original file. Not uploading.")
+      }
     }
   ], function(err){
     if(err === 'skip'){
       err = null;
     }
-    context.done(err);
+    callback(err);
+    console.log(err);
+    //context.done(err);
   });
 };
diff --git a/package.json b/package.json
index b69ad40..d378280 100644
--- a/package.json
+++ b/package.json
@@ -14,10 +14,11 @@
   },
   "dependencies": {
     "async": "^1.5.0",
-    "imagemin": "^3.2.0",
-    "imagemin-optipng": "^4.3.0"
+    "imagemin": "^5.2.0",
+    "imagemin-optipng": "^5.1.0",
+    "imagemin-jpegoptim": "^5.0.0"
   },
   "devDependencies": {
-    "node-lambda": "^0.7.1"
+    "node-lambda": "^0.8.6"
   }
 }
diff --git a/post_install.sh b/post_install.sh
new file mode 100755
index 0000000..19b9f7c
--- /dev/null
+++ b/post_install.sh
@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+# for aws lambda, we need a different jpegoptim than produced on ubuntu
+cp bin/jpegoptim.aws node_modules/jpegoptim-bin/vendor/jpegoptim
\ No newline at end of file