diff --git a/data/scripts/white_to_alpha.js b/data/scripts/white_to_alpha.js
index 81eace42a..b8ab13d9f 100644
--- a/data/scripts/white_to_alpha.js
+++ b/data/scripts/white_to_alpha.js
@@ -2,7 +2,7 @@
 // Copyright (C) 2015-2016 by David Capello
 
 var col = app.pixelColor
-var img = app.activeSprite
+var img = app.activeImage
 
 for (y=0; y<img.height; ++y) {
   for (x=0; x<img.width; ++x) {
diff --git a/src/app/CMakeLists.txt b/src/app/CMakeLists.txt
index 7234cf915..6688700e6 100644
--- a/src/app/CMakeLists.txt
+++ b/src/app/CMakeLists.txt
@@ -321,7 +321,10 @@ add_library(app-lib
   script/app_object.cpp
   script/app_scripting.cpp
   script/console_object.cpp
+  script/image_class.cpp
+  script/image_wrap.cpp
   script/sprite_class.cpp
+  script/sprite_wrap.cpp
   send_crash.cpp
   shade.cpp
   shell.cpp
diff --git a/src/app/cmd/copy_region.cpp b/src/app/cmd/copy_region.cpp
index e50f8bc7f..5a9d5500c 100644
--- a/src/app/cmd/copy_region.cpp
+++ b/src/app/cmd/copy_region.cpp
@@ -19,8 +19,11 @@ namespace app {
 namespace cmd {
 
 CopyRegion::CopyRegion(Image* dst, const Image* src,
-  const gfx::Region& region, int dst_dx, int dst_dy)
+                       const gfx::Region& region,
+                       int dst_dx, int dst_dy,
+                       bool alreadyCopied)
   : WithImage(dst)
+  , m_alreadyCopied(alreadyCopied)
 {
   // Create region to save/swap later
   for (const auto& rc : region) {
@@ -46,7 +49,8 @@ CopyRegion::CopyRegion(Image* dst, const Image* src,
 
 void CopyRegion::onExecute()
 {
-  swap();
+  if (!m_alreadyCopied)
+    swap();
 }
 
 void CopyRegion::onUndo()
diff --git a/src/app/cmd/copy_region.h b/src/app/cmd/copy_region.h
index 489abecf5..84ae13bca 100644
--- a/src/app/cmd/copy_region.h
+++ b/src/app/cmd/copy_region.h
@@ -22,8 +22,13 @@ namespace cmd {
   class CopyRegion : public Cmd
                    , public WithImage {
   public:
+    // If alreadyCopied is false, it means that onExecute() will copy
+    // pixels from src to dst. If it's true, it means that "onExecute"
+    // should do nothing, because modified pixels are alreadt on "dst"
+    // (so we use "src" as the original image).
     CopyRegion(Image* dst, const Image* src,
-      const gfx::Region& region, int src_dx, int src_dy);
+               const gfx::Region& region, int src_dx, int src_dy,
+               bool alreadyCopied = false);
 
   protected:
     void onExecute() override;
@@ -37,6 +42,7 @@ namespace cmd {
   private:
     void swap();
 
+    bool m_alreadyCopied;
     gfx::Region m_region;
     std::stringstream m_stream;
   };
diff --git a/src/app/script/app_object.cpp b/src/app/script/app_object.cpp
index d0ce3609a..56c7f73ea 100644
--- a/src/app/script/app_object.cpp
+++ b/src/app/script/app_object.cpp
@@ -11,7 +11,9 @@
 
 #include "app/script/console_object.h"
 
-#include "app/script/sprite_class.h"
+#include "app/document.h"
+#include "app/script/app_scripting.h"
+#include "app/script/sprite_wrap.h"
 #include "app/ui_context.h"
 #include "script/engine.h"
 
@@ -29,7 +31,20 @@ script::result_t App_get_activeSprite(script::ContextHandle handle)
   script::Context ctx(handle);
   app::Document* doc = UIContext::instance()->activeDocument();
   if (doc)
-    ctx.pushObject(wrap_sprite(doc), "Sprite");
+    ctx.pushObject(unwrap_engine(ctx)->wrapSprite(doc), "Sprite");
+  else
+    ctx.pushNull();
+  return 1;
+}
+
+script::result_t App_get_activeImage(script::ContextHandle handle)
+{
+  script::Context ctx(handle);
+  app::Document* doc = UIContext::instance()->activeDocument();
+  if (doc) {
+    SpriteWrap* wrap = unwrap_engine(ctx)->wrapSprite(doc);
+    ctx.pushObject(wrap->activeImage(), "Image");
+  }
   else
     ctx.pushNull();
   return 1;
@@ -55,6 +70,7 @@ const script::FunctionEntry App_methods[] = {
 };
 
 const script::PropertyEntry App_props[] = {
+  { "activeImage", App_get_activeImage, nullptr },
   { "activeSprite", App_get_activeSprite, nullptr },
   { "pixelColor", App_get_pixelColor, nullptr },
   { "version", App_get_version, nullptr },
diff --git a/src/app/script/app_scripting.cpp b/src/app/script/app_scripting.cpp
index db8c48b6d..637fb1962 100644
--- a/src/app/script/app_scripting.cpp
+++ b/src/app/script/app_scripting.cpp
@@ -11,9 +11,13 @@
 
 #include "app/script/app_scripting.h"
 
+#include "app/document.h"
 #include "app/script/app_object.h"
 #include "app/script/console_object.h"
+#include "app/script/image_class.h"
+#include "app/script/image_wrap.h"
 #include "app/script/sprite_class.h"
+#include "app/script/sprite_wrap.h"
 
 namespace app {
 
@@ -25,8 +29,51 @@ AppScripting::AppScripting(script::EngineDelegate* delegate)
   register_console_object(ctx);
 
   ctx.pushGlobalObject();
+  register_image_class(-1, ctx);
   register_sprite_class(-1, ctx);
+
+  ctx.pushPointer(this);
+  ctx.setProp(-2, script::kPtrId);
+
   ctx.pop();
 }
 
+SpriteWrap* AppScripting::wrapSprite(app::Document* doc)
+{
+  auto it = m_sprites.find(doc->id());
+  if (it != m_sprites.end())
+    return it->second;
+  else {
+    auto wrap = new SpriteWrap(doc);
+    m_sprites[doc->id()] = wrap;
+    return wrap;
+  }
+}
+
+void AppScripting::onAfterEval(bool err)
+{
+  // Commit all transactions
+  if (!err) {
+    for (auto& it : m_sprites)
+      it.second->commit();
+  }
+  destroyWrappers();
+}
+
+void AppScripting::destroyWrappers()
+{
+  for (auto& it : m_sprites)
+    delete it.second;
+  m_sprites.clear();
+}
+
+AppScripting* unwrap_engine(script::Context& ctx)
+{
+  ctx.pushGlobalObject();
+  ctx.getProp(-1, script::kPtrId);
+  void* ptr = ctx.getPointer(-1);
+  ctx.pop(2);
+  return (AppScripting*)ptr;
+}
+
 }
diff --git a/src/app/script/app_scripting.h b/src/app/script/app_scripting.h
index ac89a43d4..b44399209 100644
--- a/src/app/script/app_scripting.h
+++ b/src/app/script/app_scripting.h
@@ -5,19 +5,43 @@
 // it under the terms of the GNU General Public License version 2 as
 // published by the Free Software Foundation.
 
-#ifndef APP_SCRIPT_H_INCLUDED
-#define APP_SCRIPT_H_INCLUDED
+#ifndef APP_SCRIPTING_H_INCLUDED
+#define APP_SCRIPTING_H_INCLUDED
 #pragma once
 
+#include "doc/object_id.h"
 #include "script/engine.h"
 
+#include <map>
+
+namespace doc {
+  class Image;
+}
+
 namespace app {
+  class Document;
+  class ImageWrap;
+  class SpriteWrap;
 
   class AppScripting : public script::Engine {
+    typedef std::map<doc::ObjectId, SpriteWrap*> Sprites;
+
   public:
     AppScripting(script::EngineDelegate* delegate);
+
+    SpriteWrap* wrapSprite(app::Document* doc);
+
+  protected:
+    void onAfterEval(bool err) override;
+
+  private:
+    void destroyWrappers();
+
+    Sprites m_sprites;
   };
 
+  AppScripting* unwrap_engine(script::Context& ctx);
+
 } // namespace app
 
 #endif
diff --git a/src/app/script/image_class.cpp b/src/app/script/image_class.cpp
new file mode 100644
index 000000000..8401d4e58
--- /dev/null
+++ b/src/app/script/image_class.cpp
@@ -0,0 +1,101 @@
+// Aseprite
+// Copyright (C) 2015-2016  David Capello
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 2 as
+// published by the Free Software Foundation.
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/script/image_class.h"
+
+#include "app/script/image_wrap.h"
+#include "doc/image.h"
+
+namespace app {
+
+namespace {
+
+script::result_t Image_ctor(script::ContextHandle handle)
+{
+  return 0;
+}
+
+script::result_t Image_putPixel(script::ContextHandle handle)
+{
+  script::Context ctx(handle);
+  int x = ctx.requireInt(0);
+  int y = ctx.requireInt(1);
+  doc::color_t color = ctx.requireUInt(2);
+
+  auto wrap = (ImageWrap*)ctx.getThis();
+  if (wrap) {
+    wrap->modifyRegion(gfx::Region(gfx::Rect(x, y, 1, 1)));
+    wrap->image()->putPixel(x, y, color);
+  }
+
+  return 0;
+}
+
+script::result_t Image_getPixel(script::ContextHandle handle)
+{
+  script::Context ctx(handle);
+  int x = ctx.requireInt(0);
+  int y = ctx.requireInt(1);
+
+  auto wrap = (ImageWrap*)ctx.getThis();
+  if (wrap) {
+    doc::color_t color = wrap->image()->getPixel(x, y);
+    ctx.pushUInt(color);
+    return 1;
+  }
+  else
+    return 0;
+}
+
+script::result_t Image_get_width(script::ContextHandle handle)
+{
+  script::Context ctx(handle);
+  auto wrap = (ImageWrap*)ctx.getThis();
+  if (wrap) {
+    ctx.pushInt(wrap->image()->width());
+    return 1;
+  }
+  else
+    return 0;
+}
+
+script::result_t Image_get_height(script::ContextHandle handle)
+{
+  script::Context ctx(handle);
+  auto wrap = (ImageWrap*)ctx.getThis();
+  if (wrap) {
+    ctx.pushInt(wrap->image()->height());
+    return 1;
+  }
+  else
+    return 0;
+}
+
+const script::FunctionEntry Image_methods[] = {
+  { "getPixel", Image_getPixel, 2 },
+  { "putPixel", Image_putPixel, 3 },
+  { nullptr, nullptr, 0 }
+};
+
+const script::PropertyEntry Image_props[] = {
+  { "width", Image_get_width, nullptr },
+  { "height", Image_get_height, nullptr },
+  { nullptr, nullptr, 0 }
+};
+
+} // anonymous namespace
+
+void register_image_class(script::index_t idx, script::Context& ctx)
+{
+  ctx.registerClass(idx, "Image", Image_ctor, 0, Image_methods, Image_props);
+}
+
+} // namespace app
diff --git a/src/app/script/image_class.h b/src/app/script/image_class.h
new file mode 100644
index 000000000..4630c7c45
--- /dev/null
+++ b/src/app/script/image_class.h
@@ -0,0 +1,20 @@
+// Aseprite
+// Copyright (C) 2016  David Capello
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 2 as
+// published by the Free Software Foundation.
+
+#ifndef APP_SCRIPT_IMAGE_CLASS_H_INCLUDED
+#define APP_SCRIPT_IMAGE_CLASS_H_INCLUDED
+#pragma once
+
+#include "script/engine.h"
+
+namespace app {
+
+  void register_image_class(script::index_t idx, script::Context& ctx);
+
+} // namespace app
+
+#endif
diff --git a/src/app/script/image_wrap.cpp b/src/app/script/image_wrap.cpp
new file mode 100644
index 000000000..9b6828afc
--- /dev/null
+++ b/src/app/script/image_wrap.cpp
@@ -0,0 +1,52 @@
+// Aseprite
+// Copyright (C) 2016  David Capello
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 2 as
+// published by the Free Software Foundation.
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/script/image_wrap.h"
+
+#include "app/cmd/copy_region.h"
+#include "app/script/sprite_wrap.h"
+#include "app/transaction.h"
+#include "doc/image.h"
+
+namespace app {
+
+ImageWrap::ImageWrap(SpriteWrap* sprite, doc::Image* img)
+  : m_sprite(sprite)
+  , m_image(img)
+  , m_backup(nullptr)
+{
+}
+
+ImageWrap::~ImageWrap()
+{
+}
+
+void ImageWrap::commit()
+{
+  if (m_modifiedRegion.isEmpty())
+    return;
+
+  sprite()->transaction().execute(
+    new cmd::CopyRegion(m_image,
+                        m_backup.get(),
+                        m_modifiedRegion, 0, 0,
+                        true));
+}
+
+void ImageWrap::modifyRegion(const gfx::Region& rgn)
+{
+  if (!m_backup)
+    m_backup.reset(doc::Image::createCopy(m_image));
+
+  m_modifiedRegion |= rgn;
+}
+
+} // namespace app
diff --git a/src/app/script/image_wrap.h b/src/app/script/image_wrap.h
new file mode 100644
index 000000000..50bc03078
--- /dev/null
+++ b/src/app/script/image_wrap.h
@@ -0,0 +1,39 @@
+// Aseprite
+// Copyright (C) 2016  David Capello
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 2 as
+// published by the Free Software Foundation.
+
+#ifndef APP_SCRIPT_IMAGE_WRAP_H_INCLUDED
+#define APP_SCRIPT_IMAGE_WRAP_H_INCLUDED
+#pragma once
+
+#include "doc/image.h"
+#include "doc/image_ref.h"
+#include "gfx/region.h"
+
+namespace app {
+  class SpriteWrap;
+
+  class ImageWrap {
+  public:
+    ImageWrap(SpriteWrap* sprite, doc::Image* img);
+    ~ImageWrap();
+
+    void commit();
+
+    SpriteWrap* sprite() const { return m_sprite; }
+    doc::Image* image() const { return m_image; }
+
+    void modifyRegion(const gfx::Region& rgn);
+  private:
+    SpriteWrap* m_sprite;
+    doc::Image* m_image;
+    doc::ImageRef m_backup;
+    gfx::Region m_modifiedRegion;
+  };
+
+} // namespace app
+
+#endif
diff --git a/src/app/script/sprite_class.cpp b/src/app/script/sprite_class.cpp
index 83958616e..786aa1381 100644
--- a/src/app/script/sprite_class.cpp
+++ b/src/app/script/sprite_class.cpp
@@ -11,8 +11,11 @@
 
 #include "app/script/sprite_class.h"
 
+#include "app/cmd/set_sprite_size.h"
 #include "app/document.h"
 #include "app/document_api.h"
+#include "app/script/app_scripting.h"
+#include "app/script/sprite_wrap.h"
 #include "app/transaction.h"
 #include "app/ui/document_view.h"
 #include "app/ui_context.h"
@@ -20,30 +23,10 @@
 #include "doc/sprite.h"
 #include "script/engine.h"
 
-#include <map>
-#include <iostream>
-
 namespace app {
 
 namespace {
 
-class SpriteInScript {
-public:
-  SpriteInScript(app::Document* doc)
-    : m_doc(doc) {
-  }
-
-  ~SpriteInScript() {
-  }
-
-  app::Document* document() {
-    return m_doc;
-  }
-
-private:
-  app::Document* m_doc;
-};
-
 script::result_t Sprite_ctor(script::ContextHandle handle)
 {
   script::Context ctx(handle);
@@ -58,71 +41,22 @@ script::result_t Sprite_ctor(script::ContextHandle handle)
     sprite.release();
 
     doc->setContext(UIContext::instance());
-    ctx.pushThis(wrap_sprite(doc.release()));
+    ctx.pushThis(unwrap_engine(ctx)->wrapSprite(doc.release()));
   }
   return 0;
 }
 
-script::result_t Sprite_putPixel(script::ContextHandle handle)
-{
-  script::Context ctx(handle);
-  int x = ctx.requireInt(0);
-  int y = ctx.requireInt(1);
-  doc::color_t color = ctx.requireUInt(2);
-
-  Document* doc = (Document*)unwrap_sprite(ctx.getThis());
-  DocumentView* docView = UIContext::instance()->getFirstDocumentView(doc);
-  if (!docView)
-    return 0;
-
-  doc::Site site;
-  docView->getSite(&site);
-
-  int celX, celY;
-  doc::Image* image = site.image(&celX, &celY, nullptr);
-  if (image)
-    image->putPixel(x-celX, y-celY, color);
-
-  return 0;
-}
-
-script::result_t Sprite_getPixel(script::ContextHandle handle)
-{
-  script::Context ctx(handle);
-  int x = ctx.requireInt(0);
-  int y = ctx.requireInt(1);
-
-  Document* doc = (Document*)unwrap_sprite(ctx.getThis());
-  DocumentView* docView = UIContext::instance()->getFirstDocumentView(doc);
-  if (!docView)
-    return 0;
-
-  doc::Site site;
-  docView->getSite(&site);
-
-  int celX, celY;
-  doc::Image* image = site.image(&celX, &celY, nullptr);
-  if (image) {
-    doc::color_t color = image->getPixel(x-celX, y-celY);
-    ctx.pushUInt(color);
-    return 1;
-  }
-  else
-    return 0;
-}
-
 script::result_t Sprite_resize(script::ContextHandle handle)
 {
   script::Context ctx(handle);
   int w = ctx.requireInt(0);
   int h = ctx.requireInt(1);
 
-  Document* doc = (Document*)unwrap_sprite(ctx.getThis());
-  {
-    Transaction transaction(UIContext::instance(), "Script Execution", ModifyDocument);
-    DocumentApi api(doc, transaction);
+  auto wrap = (SpriteWrap*)ctx.getThis();
+  if (wrap) {
+    Document* doc = wrap->document();
+    DocumentApi api(doc, wrap->transaction());
     api.setSpriteSize(doc->sprite(), w, h);
-    transaction.commit();
   }
 
   return 0;
@@ -136,12 +70,11 @@ script::result_t Sprite_crop(script::ContextHandle handle)
   int w = ctx.requireInt(2);
   int h = ctx.requireInt(3);
 
-  Document* doc = (Document*)unwrap_sprite(ctx.getThis());
-  {
-    Transaction transaction(UIContext::instance(), "Script Execution", ModifyDocument);
-    DocumentApi api(doc, transaction);
+  auto wrap = (SpriteWrap*)ctx.getThis();
+  if (wrap) {
+    Document* doc = wrap->document();
+    DocumentApi api(doc, wrap->transaction());
     api.cropSprite(doc->sprite(), gfx::Rect(x, y, w, h));
-    transaction.commit();
   }
 
   return 0;
@@ -150,8 +83,8 @@ script::result_t Sprite_crop(script::ContextHandle handle)
 script::result_t Sprite_get_width(script::ContextHandle handle)
 {
   script::Context ctx(handle);
-  Document* doc = (Document*)unwrap_sprite(ctx.getThis());
-  ctx.pushInt(doc->sprite()->width());
+  auto wrap = (SpriteWrap*)ctx.getThis();
+  ctx.pushInt(wrap->sprite()->width());
   return 1;
 }
 
@@ -159,16 +92,21 @@ script::result_t Sprite_set_width(script::ContextHandle handle)
 {
   script::Context ctx(handle);
   int w = ctx.requireInt(0);
-  Document* doc = (Document*)unwrap_sprite(ctx.getThis());
-  doc->sprite()->setSize(w, doc->sprite()->height());
+  auto wrap = (SpriteWrap*)ctx.getThis();
+
+  wrap->transaction().execute(
+    new cmd::SetSpriteSize(wrap->sprite(),
+                           w,
+                           wrap->sprite()->height()));
+
   return 0;
 }
 
 script::result_t Sprite_get_height(script::ContextHandle handle)
 {
   script::Context ctx(handle);
-  Document* doc = (Document*)unwrap_sprite(ctx.getThis());
-  ctx.pushInt(doc->sprite()->height());
+  auto wrap = (SpriteWrap*)ctx.getThis();
+  ctx.pushInt(wrap->sprite()->height());
   return 1;
 }
 
@@ -176,14 +114,17 @@ script::result_t Sprite_set_height(script::ContextHandle handle)
 {
   script::Context ctx(handle);
   int h = ctx.requireInt(0);
-  Document* doc = (Document*)unwrap_sprite(ctx.getThis());
-  doc->sprite()->setSize(doc->sprite()->width(), h);
+  auto wrap = (SpriteWrap*)ctx.getThis();
+
+  wrap->transaction().execute(
+    new cmd::SetSpriteSize(wrap->sprite(),
+                           wrap->sprite()->width(),
+                           h));
+
   return 0;
 }
 
 const script::FunctionEntry Sprite_methods[] = {
-  { "getPixel", Sprite_getPixel, 2 },
-  { "putPixel", Sprite_putPixel, 3 },
   { "resize", Sprite_resize, 2 },
   { "crop", Sprite_crop, 4 },
   { nullptr, nullptr, 0 }
@@ -197,28 +138,6 @@ const script::PropertyEntry Sprite_props[] = {
 
 } // anonymous namespace
 
-static std::map<doc::ObjectId, SpriteInScript*> g_sprites;
-
-void* wrap_sprite(app::Document* doc)
-{
-  auto it = g_sprites.find(doc->id());
-  if (it != g_sprites.end())
-    return it->second;
-  else {
-    SpriteInScript* wrap = new SpriteInScript(doc);
-    g_sprites[doc->id()] = wrap;
-    return wrap;
-  }
-}
-
-app::Document* unwrap_sprite(void* ptr)
-{
-  if (ptr)
-    return ((SpriteInScript*)ptr)->document();
-  else
-    return nullptr;
-}
-
 void register_sprite_class(script::index_t idx, script::Context& ctx)
 {
   ctx.registerClass(idx, "Sprite", Sprite_ctor, 3, Sprite_methods, Sprite_props);
diff --git a/src/app/script/sprite_class.h b/src/app/script/sprite_class.h
index 98ab6e2d5..5c1ffe038 100644
--- a/src/app/script/sprite_class.h
+++ b/src/app/script/sprite_class.h
@@ -12,10 +12,6 @@
 #include "script/engine.h"
 
 namespace app {
-  class Document;
-
-  void* wrap_sprite(app::Document* doc);
-  app::Document* unwrap_sprite(void* ptr);
 
   void register_sprite_class(script::index_t idx, script::Context& ctx);
 
diff --git a/src/app/script/sprite_wrap.cpp b/src/app/script/sprite_wrap.cpp
new file mode 100644
index 000000000..cfdbbef02
--- /dev/null
+++ b/src/app/script/sprite_wrap.cpp
@@ -0,0 +1,96 @@
+// Aseprite
+// Copyright (C) 2016  David Capello
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 2 as
+// published by the Free Software Foundation.
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/script/sprite_wrap.h"
+
+#include "app/cmd/set_sprite_size.h"
+#include "app/document.h"
+#include "app/document_api.h"
+#include "app/script/image_wrap.h"
+#include "app/transaction.h"
+#include "app/ui/document_view.h"
+#include "app/ui_context.h"
+#include "doc/site.h"
+#include "doc/sprite.h"
+
+namespace app {
+
+SpriteWrap::SpriteWrap(app::Document* doc)
+  : m_doc(doc)
+  , m_view(UIContext::instance()->getFirstDocumentView(m_doc))
+  , m_transaction(nullptr)
+{
+}
+
+SpriteWrap::~SpriteWrap()
+{
+  for (auto it : m_images)
+    delete it.second;
+
+  if (m_transaction)
+    delete m_transaction;
+}
+
+Transaction& SpriteWrap::transaction()
+{
+  if (!m_transaction) {
+    m_transaction = new Transaction(UIContext::instance(),
+                                    "Script Execution",
+                                    ModifyDocument);
+  }
+  return *m_transaction;
+}
+
+void SpriteWrap::commit()
+{
+  for (auto it : m_images)
+    it.second->commit();
+
+  if (m_transaction) {
+    m_transaction->commit();
+    delete m_transaction;
+    m_transaction = nullptr;
+  }
+}
+
+app::Document* SpriteWrap::document()
+{
+  return m_doc;
+}
+
+doc::Sprite* SpriteWrap::sprite()
+{
+  return m_doc->sprite();
+}
+
+ImageWrap* SpriteWrap::activeImage()
+{
+  if (!m_view)
+    return nullptr;
+
+  doc::Site site;
+  m_view->getSite(&site);
+  return wrapImage(site.image());
+}
+
+ImageWrap* SpriteWrap::wrapImage(doc::Image* img)
+{
+  auto it = m_images.find(img->id());
+  if (it != m_images.end())
+    return it->second;
+  else {
+    auto wrap = new ImageWrap(this, img);
+    m_images[img->id()] = wrap;
+    return wrap;
+  }
+}
+
+} // namespace app
diff --git a/src/app/script/sprite_wrap.h b/src/app/script/sprite_wrap.h
new file mode 100644
index 000000000..5b4f05c37
--- /dev/null
+++ b/src/app/script/sprite_wrap.h
@@ -0,0 +1,53 @@
+// Aseprite
+// Copyright (C) 2016  David Capello
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 2 as
+// published by the Free Software Foundation.
+
+#ifndef APP_SCRIPT_SPRITE_WRAP_H_INCLUDED
+#define APP_SCRIPT_SPRITE_WRAP_H_INCLUDED
+#pragma once
+
+#include "doc/object_id.h"
+
+#include <map>
+
+namespace doc {
+  class Image;
+  class Sprite;
+}
+
+namespace app {
+  class Document;
+  class DocumentView;
+  class ImageWrap;
+  class Transaction;
+
+  class SpriteWrap {
+    typedef std::map<doc::ObjectId, ImageWrap*> Images;
+
+  public:
+    SpriteWrap(app::Document* doc);
+    ~SpriteWrap();
+
+    void commit();
+    Transaction& transaction();
+
+    app::Document* document();
+    doc::Sprite* sprite();
+    ImageWrap* activeImage();
+
+    ImageWrap* wrapImage(doc::Image* img);
+
+  private:
+    app::Document* m_doc;
+    app::DocumentView* m_view;
+    app::Transaction* m_transaction;
+
+    Images m_images;
+  };
+
+} // namespace app
+
+#endif
diff --git a/src/script/engine.cpp b/src/script/engine.cpp
index bc54660d0..eea3c587c 100644
--- a/src/script/engine.cpp
+++ b/src/script/engine.cpp
@@ -30,6 +30,8 @@ public:
 
 namespace script {
 
+const char* kPtrId = "\xFF" "\xFF" "ptr";
+
 namespace {
 
 // TODO classes in modules isn't supported yet
@@ -108,6 +110,11 @@ void Context::pop()
   duk_pop(m_handle);
 }
 
+void Context::pop(index_t count)
+{
+  duk_pop_n(m_handle, count);
+}
+
 void Context::remove(index_t idx)
 {
   duk_remove(m_handle, idx);
@@ -193,6 +200,11 @@ const char* Context::toString(index_t i)
   return duk_to_string(m_handle, i);
 }
 
+void* Context::getPointer(index_t i)
+{
+  return duk_get_pointer(m_handle, i);
+}
+
 bool Context::requireBool(index_t i)
 {
   return (duk_require_boolean(m_handle, i) ? true: false);
@@ -220,7 +232,7 @@ const char* Context::requireString(index_t i)
 
 void* Context::requireObject(index_t i, const char* className)
 {
-  duk_get_prop_string(m_handle, i, "\xFF" "\xFF" "ptr");
+  duk_get_prop_string(m_handle, i, kPtrId);
   void* result = (void*)duk_to_pointer(m_handle, -1);
   // TODO check pointer type
   duk_pop(m_handle);
@@ -276,7 +288,12 @@ void Context::pushThis(void* ptr)
 {
   duk_push_this(m_handle);
   duk_push_pointer(m_handle, ptr);
-  duk_put_prop_string(m_handle, -2, "\xFF" "\xFF" "ptr");
+  duk_put_prop_string(m_handle, -2, kPtrId);
+}
+
+void Context::pushPointer(void* ptr)
+{
+  duk_push_pointer(m_handle, ptr);
 }
 
 index_t Context::pushObject()
@@ -288,7 +305,7 @@ index_t Context::pushObject(void* ptr, const char* className)
 {
   index_t obj = duk_push_object(m_handle);
   duk_push_pointer(m_handle, ptr);
-  duk_put_prop_string(m_handle, obj, "\xFF" "\xFF" "ptr");
+  duk_put_prop_string(m_handle, obj, kPtrId);
 
   // TODO classes in modules isn't supported yet
   duk_get_global_string(m_handle, className);
@@ -395,7 +412,7 @@ void Context::registerClass(index_t idx,
 void* Context::getThis()
 {
   duk_push_this(m_handle);
-  duk_get_prop_string(m_handle, -1, "\xFF" "\xFF" "ptr");
+  duk_get_prop_string(m_handle, -1, kPtrId);
   void* result = (void*)duk_to_pointer(m_handle, -1);
   duk_pop_2(m_handle);
   return result;
@@ -445,6 +462,8 @@ void Engine::printLastResult()
 
 void Engine::eval(const std::string& jsCode)
 {
+  bool errFlag = true;
+  onBeforeEval();
   try {
     ContextHandle handle = m_ctx.handle();
 
@@ -453,18 +472,23 @@ void Engine::eval(const std::string& jsCode)
     if (m_printLastResult &&
         !duk_is_null_or_undefined(handle, -1)) {
       m_delegate->onConsolePrint(duk_safe_to_string(handle, -1));
+    }
 
     duk_pop(handle);
+    errFlag = false;
   }
   catch (const std::exception& ex) {
     std::string err = "Error: ";
     err += ex.what();
     m_delegate->onConsolePrint(err.c_str());
   }
+  onAfterEval(errFlag);
 }
 
 void Engine::evalFile(const std::string& file)
 {
+  bool errFlag = true;
+  onBeforeEval();
   try {
     ContextHandle handle = m_ctx.handle();
 
@@ -497,14 +521,17 @@ void Engine::evalFile(const std::string& file)
     if (m_printLastResult &&
         !duk_is_null_or_undefined(handle, -1)) {
       m_delegate->onConsolePrint(duk_safe_to_string(handle, -1));
+    }
 
     duk_pop(handle);
+    errFlag = false;
   }
   catch (const std::exception& ex) {
     std::string err = "Error: ";
     err += ex.what();
     m_delegate->onConsolePrint(err.c_str());
   }
+  onAfterEval(errFlag);
 }
 
 void Engine::registerModule(Module* module)
diff --git a/src/script/engine.h b/src/script/engine.h
index ec9534a14..fc6e2a515 100644
--- a/src/script/engine.h
+++ b/src/script/engine.h
@@ -21,6 +21,8 @@ namespace script {
   typedef struct duk_hthread* ContextHandle;
   typedef result_t (*Function)(ContextHandle ctx);
 
+  extern const char* kPtrId;
+
   struct FunctionEntry {
     const char* id;
     Function value;
@@ -48,6 +50,7 @@ namespace script {
 
     void dump();
     void pop();
+    void pop(index_t count);
     void remove(index_t idx);
     void duplicateTop();
 
@@ -68,6 +71,7 @@ namespace script {
     unsigned int getUInt(index_t i);
     const char* getString(index_t i);
     const char* toString(index_t i);
+    void* getPointer(index_t i);
     void* getThis();
 
     bool hasProp(index_t i, const char* propName);
@@ -91,6 +95,7 @@ namespace script {
     void pushString(const char* str);
     void pushThis();
     void pushThis(void* ptr);
+    void pushPointer(void* ptr);
     index_t pushObject();
     index_t pushObject(void* ptr, const char* className);
     void pushGlobalObject();
@@ -134,6 +139,10 @@ namespace script {
 
     void registerModule(Module* module);
 
+  protected:
+    virtual void onBeforeEval() { }
+    virtual void onAfterEval(bool err) { }
+
   private:
     Context m_ctx;
     EngineDelegate* m_delegate;