diff --git a/lib/images.js b/lib/images.js
index 36e8f5a..bbeff12 100644
--- a/lib/images.js
+++ b/lib/images.js
@@ -20,11 +20,14 @@ function applyImageMethods(constructor) {
   //   pass.icon(function(callback) { ... };
   //   console.log(pass.icon());
   //
-  // The 2x suffix is used for high resolution version (file name uses @2x
-  // suffix).
+  // The 2x and 3x suffix is used for high resolution version (file name uses
+  // @2x or @3x suffix).
   //
   //   pass.icon2x("icon@2x.png");
   //   console.log(pass.icon2x());
+  //
+  //   pass.icon3x("icon@3x.png");
+  //   console.log(pass.icon3x());
   IMAGES.forEach(function(key) {
     prototype[key] = function(value) {
       if (arguments.length === 0) {
@@ -35,12 +38,22 @@ function applyImageMethods(constructor) {
       }
     };
 
-    var retina = key + "2x";
-    prototype[retina] = function(value) {
+    var retina2x = key + "2x";
+    prototype[retina2x] = function(value) {
+      if (arguments.length === 0) {
+        return this.images[retina2x];
+      } else {
+        this.images[retina2x] = value;
+        return this;
+      }
+    };
+
+    var retina3x = key + "3x";
+    prototype[retina3x] = function(value) {
       if (arguments.length === 0) {
-        return this.images[retina];
+        return this.images[retina3x];
       } else {
-        this.images[retina] = value;
+        this.images[retina3x] = value;
         return this;
       }
     };
@@ -56,8 +69,11 @@ function applyImageMethods(constructor) {
     var files = File.readdirSync(path);
     files.forEach(function(filename) {
       var basename = Path.basename(filename, ".png");
-      if (/@2x$/.test(basename) && ~IMAGES.indexOf(basename.slice(0, -3))) {
-        // High resolution
+      if (/@3x$/.test(basename) && ~IMAGES.indexOf(basename.slice(0, -3))) {
+        // High resolution 3x
+        self.images[basename.replace(/@3x$/, "3x")] = Path.resolve(path, filename);
+      } else if (/@2x$/.test(basename) && ~IMAGES.indexOf(basename.slice(0, -3))) {
+        // High resolution 2x
         self.images[basename.replace(/@2x$/, "2x")] = Path.resolve(path, filename);
       } else if (~IMAGES.indexOf(basename)) {
         // Normal resolution
diff --git a/lib/pass.js b/lib/pass.js
index 3fefcfd..2c18bce 100644
--- a/lib/pass.js
+++ b/lib/pass.js
@@ -11,13 +11,14 @@ var HTTP              = require("http");
 var HTTPS             = require("https");
 var Path              = require("path");
 var Zip               = require("./zip");
+var async             = require("async");
 var zlib              = require("zlib");
 
 
 // Top-level pass fields.
 var TOP_LEVEL           = [ "authenticationToken", "backgroundColor", "barcode", "description",
                             "foregroundColor", "labelColor", "locations", "logoText",
-                            "organizationName", "relevantDate", "serialNumber", 
+                            "organizationName", "relevantDate", "serialNumber",
                             "suppressStripShine", "webServiceURL"];
 // These top level fields are required for a valid pass.
 var REQUIRED_TOP_LEVEL  = [ "description", "organizationName", "passTypeIdentifier",
@@ -33,9 +34,11 @@ var REQUIRED_IMAGES     = [ "icon", "logo" ];
 
 // Create a new pass.
 //
-// template  - The template
-// fields    - Pass fields (description, serialNumber, logoText)
-function Pass(template, fields, images) {
+// tempplate  - The template
+// fields     - Pass fields (description, serialNumber, logoText)
+function Pass(template, fields, images, mockSignature, mockModifiedDate) {
+  this.mockSignature = mockSignature
+  this.mockModifiedDate = mockModifiedDate
   this.template = template;
   this.fields = cloneObject(fields);
   // Structure is basically reference to all the fields under a given style
@@ -139,7 +142,7 @@ Fields.prototype.add = function(key, label, value, options) {
 // key      - Field key
 // label    - Field label (optional)
 // value    - Field value
-// Other field options (e.g. dateStyle) 
+// Other field options (e.g. dateStyle)
 Fields.prototype.get = function(key) {
   var fields = this.pass.structure[this.key];
   if (fields) {
@@ -210,6 +213,8 @@ Pass.prototype.pipe = function(output) {
   var self = this;
   var zip = new Zip(output);
   var lastError;
+  var doneImages = false;
+  var doneLocals = false;
 
   zip.on("error", function(error) {
     lastError = error;
@@ -228,30 +233,38 @@ Pass.prototype.pipe = function(output) {
   // Construct manifest here
   var manifest = {};
   // Add file to zip and it's SHA to manifest
-  function addFile(filename) {
-    var file = zip.addFile(filename);
+  function addFile(filename, modified) {
+    var file = zip.addFile(filename, modified);
     var sha = new SHAWriteStream(manifest, filename, file);
     return sha;
   }
 
   // Create pass.json
   var passJson = new Buffer(JSON.stringify(this.getPassJSON()), "utf-8");
-  addFile("pass.json").end(passJson, "utf8");
-
-  var expecting = 0;
-  for (var key in this.images) {
-    var filename = key.replace(/2x$/, "@2x") + ".png";
-    addImage(addFile(filename), this.images[key], function(error) {
-      --expecting;
-      if (error)
-        lastError = error;
-      if (expecting === 0)
-        doneWithImages();
-    });
-    ++expecting;
-  }
+  addFile("pass.json", self.mockModifiedDate).end(passJson, "utf8");
+
+  var pass = this
+  async.eachSeries(Object.keys(pass.images), function (key, cb) {
+    var filename = key.replace(/3x$/, "@3x");
+    filename = filename.replace(/2x$/, "@2x");
+    filename += ".png";
+    writeFile(addFile(filename, self.mockModifiedDate), pass.images[key], cb);
+  }, function(err) {
+    if (err) {
+      lastError = err;
+      doneWithWriting();
+    } else {
+      if(!pass.localizations) return doneWithWriting();
+      async.eachSeries(Object.keys(pass.localizations), function (key, cb) {
+        writeFile(addFile(key, self.mockModifiedDate), pass.localizations[key], cb);
+      }, function(err) {
+        if (err) lastError = err;
+        doneWithWriting();
+      })
+    }
+  });
 
-  function doneWithImages() {
+  function doneWithWriting() {
     if (lastError) {
       zip.close();
       self.emit("error", lastError);
@@ -268,7 +281,7 @@ Pass.prototype.pipe = function(output) {
           zip.on("error", function(error) {
             self.emit("error", error);
           });
-        });
+        }, self.mockSignature, self.mockModifiedDate);
       });
     }
   }
@@ -291,7 +304,7 @@ Pass.prototype.render = function(response, callback) {
 };
 
 
-function addImage(file, source, callback) {
+function writeFile(file, source, callback) {
   if (typeof(source) == "string" || source instanceof String) {
     if (/^https?:/i.test(source)) {
       // URL
@@ -331,17 +344,56 @@ function addImage(file, source, callback) {
   }
 }
 
+function addLocalFile(file, source, callback) {
+  if (typeof(source) == "string" || source instanceof String) {
+    if (/^https?:/i.test(source)) {
+      // URL
+      var protocol = /^https:/i.test(source) ? HTTPS : HTTP;
+      protocol.get(source, function(response) {
+        if (response.statusCode == 200) {
+          response.on("end", callback);
+          response.pipe(file);
+          response.resume();
+        } else
+          callback(new Error("Server returned " + response.statusCode + " for " + source));
+      }).on("error", callback);
+    } else {
+      // Assume filename
+      var stream = File.createReadStream(source);
+      stream.pipe(file);
+      file.on("close", callback);
+    }
+  } else if (source instanceof Buffer) {
+    file.on("close", callback);
+    file.write(source);
+    file.end();
+  } else if (typeof(source) == "function") {
+    try {
+      source(file);
+      callback();
+    } catch (error) {
+      callback(error);
+    }
+  } else {
+    // image is not a supported type
+    callback(new Error("Cannot load image " + file.filename + ", must be String (filename), Buffer or function"));
+  }
+}
 
 // Add manifest.json and signature files.
-Pass.prototype.signZip = function(zip, manifest, callback) {
+Pass.prototype.signZip = function(zip, manifest, callback, mockSignature, mockModifiedDate) {
   var json = JSON.stringify(manifest);
   // Add manifest.json
-  zip.addFile("manifest.json").end(json, "utf-8");
+  zip.addFile("manifest.json", mockModifiedDate).end(json, "utf-8");
   // Create signature
   signManifest(this.template, json, function(error, signature) {
     if (!error) {
       // Write signature file
-      zip.addFile("signature").end(signature);
+      if (mockSignature) {
+        zip.addFile("signature", mockModifiedDate).end(mockSignature);
+      } else {
+        zip.addFile("signature", mockModifiedDate).end(signature);
+      }
     }
     callback(error);
   });
@@ -360,9 +412,7 @@ function signManifest(template, manifest, callback) {
     "-passin",    "pass:" + template.password
   ];
   var sign = execFile("openssl", args, { stdio: "pipe" }, function(error, stdout, stderr) {
-    var trimmedStderr = stderr.trim(); 
-    // Windows outputs some unhelpful error messages, but still produces a valid signature
-    if (error || (trimmedStderr && trimmedStderr.indexOf('- done') < 0)) {
+    if (error) {
       callback(new Error(stderr));
     } else {
       var signature = stdout.split(/\n\n/)[3];
diff --git a/lib/template.js b/lib/template.js
index abc9895..b3bee3a 100644
--- a/lib/template.js
+++ b/lib/template.js
@@ -16,7 +16,7 @@ var TEMPLATE            = [ "passTypeIdentifier", "teamIdentifier",
 // Create a new template.
 //
 // style  - Pass style (coupon, eventTicket, etc)
-// fields - Pass fields (passTypeIdentifier, teamIdentifier, etc) 
+// fields - Pass fields (passTypeIdentifier, teamIdentifier, etc)
 function Template(style, fields) {
   if (!~STYLES.indexOf(style))
     throw new Error("Unsupported pass style " + style);
@@ -44,14 +44,15 @@ Template.prototype.keys = function(path, password) {
 
 
 // Create a new pass from a template.
-Template.prototype.createPass = function(fields) {
+Template.prototype.createPass = function(fields, mocks) {
   // Combine template and pass fields
   var combined = {};
   for (var k1 in this.fields)
     combined[k1] = this.fields[k1];
   for (var k2 in fields)
     combined[k2] = fields[k2];
-  return new Pass(this, combined, this.images);
+
+  return new Pass(this, combined, this.images, mocks && mocks.signature || undefined, mocks && mocks.modifiedDate || undefined);
 };