Index: chrome/browser/extensions/extension_tabs_module.cc
===================================================================
--- chrome/browser/extensions/extension_tabs_module.cc	(revision 39038)
+++ chrome/browser/extensions/extension_tabs_module.cc	(working copy)
@@ -5,6 +5,7 @@
 #include "chrome/browser/extensions/extension_tabs_module.h"
 
 #include "app/gfx/codec/jpeg_codec.h"
+#include "app/gfx/codec/png_codec.h"
 #include "base/base64.h"
 #include "base/string_util.h"
 #include "chrome/browser/browser.h"
@@ -734,11 +735,42 @@
   Browser* browser;
   // windowId defaults to "current" window.
   int window_id = -1;
+  quality_ = 90;
+  image_format_ = IMAGE_JPEG;
 
   if (!args_->IsType(Value::TYPE_NULL)) {
-    EXTENSION_FUNCTION_VALIDATE(args_->GetAsInteger(&window_id));
+    if (args_->IsType(Value::TYPE_INTEGER)) {
+      args_->GetAsInteger(&window_id);
+    } else if (args_->IsType(Value::TYPE_DICTIONARY)) {
+        const DictionaryValue* params = args_as_dictionary();
+      if (params->HasKey(keys::kWindowIdKey)) {
+        EXTENSION_FUNCTION_VALIDATE(params->GetInteger(
+                      keys::kWindowIdKey,
+                      &window_id));
+      }
+      if (params->HasKey(keys::kQualityKey)) {
+        EXTENSION_FUNCTION_VALIDATE(params->GetInteger(
+                      keys::kQualityKey,
+                      &quality_));
+      }
+      if (params->HasKey(keys::kFormatKey)) {
+        std::string format;
+        EXTENSION_FUNCTION_VALIDATE(params->GetString(
+                      keys::kFormatKey,
+                      &format));
+        if (!format.compare(keys::kFormatValueJpeg) ) {
+          image_format_ = IMAGE_JPEG;
+        } else if (!format.compare(keys::kFormatValuePng) ) {
+          image_format_ = IMAGE_PNG;
+        } else {
+          error_ = keys::kNotSuuportedFormatError;
+          return false;
+        }
+      }
+    }
     browser = GetBrowserInProfileWithId(profile(), window_id, &error_);
-  } else {
+  }
+  if ( window_id == -1 ) {
     browser = dispatcher()->GetBrowser();
   }
 
@@ -822,14 +854,26 @@
 // and call SendResponse().
 void CaptureVisibleTabFunction::SendResultFromBitmap(
     const SkBitmap& screen_capture) {
-  scoped_refptr<RefCountedBytes> jpeg_data(new RefCountedBytes);
+  scoped_refptr<RefCountedBytes> bitmap_data(new RefCountedBytes);
   SkAutoLockPixels screen_capture_lock(screen_capture);
-  bool encoded = gfx::JPEGCodec::Encode(
-      reinterpret_cast<unsigned char*>(screen_capture.getAddr32(0, 0)),
-      gfx::JPEGCodec::FORMAT_BGRA, screen_capture.width(),
-      screen_capture.height(),
-      static_cast<int>(screen_capture.rowBytes()), 90,
-      &jpeg_data->data);
+  bool encoded = false;
+  if (IMAGE_JPEG == image_format_) {
+    encoded = gfx::JPEGCodec::Encode(
+        reinterpret_cast<unsigned char*>(screen_capture.getAddr32(0, 0)),
+        gfx::JPEGCodec::FORMAT_BGRA, screen_capture.width(),
+        screen_capture.height(),
+        static_cast<int>(screen_capture.rowBytes()), quality_,
+        &bitmap_data->data);
+  } else if (IMAGE_PNG == image_format_) {
+    encoded = gfx::PNGCodec::Encode(
+        reinterpret_cast<unsigned char*>(screen_capture.getAddr32(0, 0)),
+        gfx::PNGCodec::FORMAT_BGRA, screen_capture.width(),
+        screen_capture.height(),
+        static_cast<int>(screen_capture.rowBytes()), false,
+        &bitmap_data->data);
+  } else {
+    NOTREACHED();
+  }
   if (!encoded) {
     error_ = ExtensionErrorUtils::FormatErrorMessage(
         keys::kInternalVisibleTabCaptureError, "");
@@ -839,13 +883,16 @@
 
   std::string base64_result;
   std::string stream_as_string;
-  stream_as_string.resize(jpeg_data->data.size());
+  stream_as_string.resize(bitmap_data->data.size());
   memcpy(&stream_as_string[0],
-      reinterpret_cast<const char*>(&jpeg_data->data[0]),
-      jpeg_data->data.size());
+      reinterpret_cast<const char*>(&bitmap_data->data[0]),
+      bitmap_data->data.size());
 
   base::Base64Encode(stream_as_string, &base64_result);
-  base64_result.insert(0, "data:image/jpg;base64,");
+  const char* mime_subtypes[] = {keys::kFormatValueJpeg, keys::kFormatValuePng};
+  std::string mime = "data:image/";
+  mime = mime + mime_subtypes[image_format_] + ";base64,";
+  base64_result.insert(0, mime.c_str());
   result_.reset(new StringValue(base64_result));
   SendResponse(true);
 }
Index: chrome/browser/extensions/extension_tabs_module.h
===================================================================
--- chrome/browser/extensions/extension_tabs_module.h	(revision 39038)
+++ chrome/browser/extensions/extension_tabs_module.h	(working copy)
@@ -141,6 +141,10 @@
                                   public NotificationObserver {
  private:
   ~CaptureVisibleTabFunction() {}
+  enum ImageFormat {
+    IMAGE_JPEG,
+    IMAGE_PNG
+  };
   virtual bool RunImpl();
   virtual void CaptureSnapshotFromBackingStore(BackingStore* backing_store);
   virtual void Observe(NotificationType type,
@@ -149,6 +153,8 @@
   virtual void SendResultFromBitmap(const SkBitmap& screen_capture);
 
   NotificationRegistrar registrar_;
+  ImageFormat image_format_;
+  int quality_;
 
   DECLARE_EXTENSION_FUNCTION_NAME("tabs.captureVisibleTab")
 };
Index: chrome/browser/extensions/extension_tabs_module_constants.cc
===================================================================
--- chrome/browser/extensions/extension_tabs_module_constants.cc	(revision 39038)
+++ chrome/browser/extensions/extension_tabs_module_constants.cc	(working copy)
@@ -11,6 +11,7 @@
 const wchar_t kFavIconUrlKey[] = L"favIconUrl";
 const wchar_t kFileKey[] = L"file";
 const wchar_t kFocusedKey[] = L"focused";
+const wchar_t kFormatKey[] = L"format";
 const wchar_t kFromIndexKey[] = L"fromIndex";
 const wchar_t kHeightKey[] = L"height";
 const wchar_t kIdKey[] = L"id";
@@ -21,6 +22,7 @@
 const wchar_t kOldPositionKey[] = L"oldPosition";
 const wchar_t kOldWindowIdKey[] = L"oldWindowId";
 const wchar_t kPopulateKey[] = L"populate";
+const wchar_t kQualityKey[] = L"quality";
 const wchar_t kSelectedKey[] = L"selected";
 const wchar_t kStatusKey[] = L"status";
 const wchar_t kTabIdKey[] = L"tabId";
@@ -33,6 +35,9 @@
 const wchar_t kWidthKey[] = L"width";
 const wchar_t kWindowIdKey[] = L"windowId";
 
+const char kFormatValueJpeg[] = "jpeg";
+const char kFormatValuePng[] = "png";
+
 const char kStatusValueComplete[] = "complete";
 const char kStatusValueLoading[] = "loading";
 
@@ -55,6 +60,7 @@
 const char kMoreThanOneValuesError[] = "Code and file should not be specified "
     "at the same time in the second argument.";
 const char kLoadFileError[] = "Failed to load file: \"*\". ";
+const char kNotSuuportedFormatError[] = "Not supported image format";
 const char kCannotUpdatePinnedTab[] = "Cannot update pinned tabs";
 const char kCannotRemovePhantomTab[] = "Cannot remove phantom tabs";
 const char kCannotDetermineLanguageOfUnloadedTab[] =
Index: chrome/browser/extensions/extension_tabs_module_constants.h
===================================================================
--- chrome/browser/extensions/extension_tabs_module_constants.h	(revision 39038)
+++ chrome/browser/extensions/extension_tabs_module_constants.h	(working copy)
@@ -15,6 +15,7 @@
 extern const wchar_t kFavIconUrlKey[];
 extern const wchar_t kFileKey[];
 extern const wchar_t kFocusedKey[];
+extern const wchar_t kFormatKey[];
 extern const wchar_t kFromIndexKey[];
 extern const wchar_t kHeightKey[];
 extern const wchar_t kIdKey[];
@@ -25,6 +26,7 @@
 extern const wchar_t kOldPositionKey[];
 extern const wchar_t kOldWindowIdKey[];
 extern const wchar_t kPopulateKey[];
+extern const wchar_t kQualityKey[];
 extern const wchar_t kSelectedKey[];
 extern const wchar_t kStatusKey[];
 extern const wchar_t kTabIdKey[];
@@ -38,6 +40,9 @@
 extern const wchar_t kWindowIdKey[];
 
 // Value consts.
+extern const char kFormatValueJpeg[];
+extern const char kFormatValuePng[];
+
 extern const char kStatusValueComplete[];
 extern const char kStatusValueLoading[];
 
@@ -57,6 +62,7 @@
 extern const char kNoCodeOrFileToExecuteError[];
 extern const char kMoreThanOneValuesError[];
 extern const char kLoadFileError[];
+extern const char kNotSuuportedFormatError[];
 extern const char kCannotUpdatePinnedTab[];
 extern const char kCannotRemovePhantomTab[];
 extern const char kCannotDetermineLanguageOfUnloadedTab[];
Index: chrome/common/extensions/api/extension_api.json
===================================================================
--- chrome/common/extensions/api/extension_api.json	(revision 39038)
+++ chrome/common/extensions/api/extension_api.json	(working copy)
@@ -875,11 +875,27 @@
         "description": "Captures the visible area of the currently selected tab in the specified window.",
         "parameters": [
           {
-            "type": "integer",
-            "name": "windowId",
-            "minimum": 0,
-            "optional": true,
-            "description": "The target window. Defaults to the <a href='windows.html#current-window'>current window</a>."
+            "name": "windowIdOrParams",
+            "choices": [
+              {
+                "type": "integer",
+                "name": "windowId",
+                "minimum": 0,
+                "optional": true,
+                "description": "The target window. Defaults to the <a href='windows.html#current-window'>current window</a>."
+              },
+              {
+                "type": "object",
+                "name": "params",
+                "optional": true,
+                "properties": {
+                  "windowId": {"type": "integer", "optional": true, "minimum": 0, "description": "The target window. Defaults to the <a href='windows.html#current-window'>current window</a>."},
+                  "format": {"type": "string", "optional": true, "description": "The image format of capture. Defaults to jpeg. Available formats are: jpeg and png."},
+                  "quality": {"type": "integer", "optional": true, "maximum": 100, "description":"Quality of capture. Effective only when format is jpeg."}
+                },
+                "description": "Parameters to control details of capture."
+              }
+            ]
           },
           {
             "type": "function", "name": "callback", "parameters": [