Index: chrome/browser/extensions/extension_tabs_module.cc
===================================================================
--- chrome/browser/extensions/extension_tabs_module.cc	(revision 29096)
+++ 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/string_util.h"
 #include "chrome/browser/browser.h"
 #include "chrome/browser/browser_list.h"
@@ -716,19 +717,50 @@
   Browser* browser;
   // windowId defaults to "current" window.
   int window_id = -1;
+  int quality = 90;
+  ImageFormat image_format = IMAGE_JPEG;
 
-  if (!args_->IsType(Value::TYPE_NULL)) {
-    EXTENSION_FUNCTION_VALIDATE(args_->GetAsInteger(&window_id));
+  EXTENSION_FUNCTION_VALIDATE(args_->IsType(Value::TYPE_LIST));
+  const ListValue* args = static_cast<const ListValue*>(args_);
+
+  Value* val;
+  args->Get(0, &val);
+  if (!val->IsType(Value::TYPE_NULL)) {
+    EXTENSION_FUNCTION_VALIDATE(val->GetAsInteger(&window_id));
     browser = GetBrowserInProfileWithId(profile(), window_id, &error_);
   } else {
     browser = dispatcher()->GetBrowser();
   }
-
   if (!browser) {
     error_ = keys::kNoCurrentWindowError;
     return false;
   }
 
+  args->Get(1, &val);
+  if (!val->IsType(Value::TYPE_NULL)) {
+    EXTENSION_FUNCTION_VALIDATE(val->IsType(Value::TYPE_DICTIONARY));
+    const DictionaryValue* params = static_cast<const DictionaryValue*>(val);
+    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;
+      }
+    }
+  }
+
   SkBitmap screen_capture;
   TabContents* tab_contents = browser->GetSelectedTabContents();
   if (!tab_contents) {
@@ -783,14 +815,26 @@
   error_ = keys::kNotImplementedError;
   return false;
 #endif
-  scoped_refptr<RefCountedBytes> jpeg_data(new RefCountedBytes);
+  scoped_refptr<RefCountedBytes> bitmapdata(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,
+        &bitmapdata->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,
+        &bitmapdata->data);
+  } else {
+    NOTREACHED();
+  }
   if (!encoded) {
     error_ = ExtensionErrorUtils::FormatErrorMessage(
         keys::kInternalVisibleTabCaptureError, "");
@@ -799,13 +843,16 @@
 
   std::string base64_result;
   std::string stream_as_string;
-  stream_as_string.resize(jpeg_data->data.size());
+  stream_as_string.resize(bitmapdata->data.size());
   memcpy(&stream_as_string[0],
-      reinterpret_cast<const char*>(&jpeg_data->data[0]),
-      jpeg_data->data.size());
-
+      reinterpret_cast<const char*>(&bitmapdata->data[0]),
+      bitmapdata->data.size());
+  
   net::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));
   return true;
 }
Index: chrome/browser/extensions/extension_tabs_module.h
===================================================================
--- chrome/browser/extensions/extension_tabs_module.h	(revision 29096)
+++ chrome/browser/extensions/extension_tabs_module.h	(working copy)
@@ -120,6 +120,10 @@
   DECLARE_EXTENSION_FUNCTION_NAME("tabs.detectLanguage")
 };
 class CaptureVisibleTabFunction : public SyncExtensionFunction {
+  enum ImageFormat {
+    IMAGE_JPEG,
+    IMAGE_PNG
+  };
   virtual bool RunImpl();
   DECLARE_EXTENSION_FUNCTION_NAME("tabs.captureVisibleTab")
 };
Index: chrome/browser/extensions/extension_tabs_module_constants.cc
===================================================================
--- chrome/browser/extensions/extension_tabs_module_constants.cc	(revision 29096)
+++ chrome/browser/extensions/extension_tabs_module_constants.cc	(working copy)
@@ -8,6 +8,7 @@
 
 const wchar_t kFavIconUrlKey[] = L"favIconUrl";
 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";
@@ -18,6 +19,7 @@
 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";
@@ -30,6 +32,9 @@
 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";
 
@@ -50,5 +55,6 @@
 const char kMoreThanOneValuesError[] = "There should be only one value (either"
                                        "code or file) in the second argument.";
 const char kLoadFileError[] = "Failed to load file: \"*\". ";
+const char kNotSuuportedFormatError[] = "Not supported image format";
 
 }  // namespace extension_tabs_module_constants
Index: chrome/browser/extensions/extension_tabs_module_constants.h
===================================================================
--- chrome/browser/extensions/extension_tabs_module_constants.h	(revision 29096)
+++ chrome/browser/extensions/extension_tabs_module_constants.h	(working copy)
@@ -12,6 +12,7 @@
 // Keys used in serializing tab data & events.
 extern const wchar_t kFavIconUrlKey[];
 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[];
@@ -22,6 +23,7 @@
 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[];
@@ -35,6 +37,9 @@
 extern const wchar_t kWindowIdKey[];
 
 // Value consts.
+extern const char kFormatValueJpeg[];
+extern const char kFormatValuePng[];
+
 extern const char kStatusValueComplete[];
 extern const char kStatusValueLoading[];
 
@@ -53,6 +58,7 @@
 extern const char kNoCodeOrFileToExecuteError[];
 extern const char kMoreThanOneValuesError[];
 extern const char kLoadFileError[];
+extern const char kNotSuuportedFormatError[];
 
 };  // namespace extension_tabs_module_constants
 
Index: chrome/common/extensions/api/extension_api.json
===================================================================
--- chrome/common/extensions/api/extension_api.json	(revision 29096)
+++ chrome/common/extensions/api/extension_api.json	(working copy)
@@ -589,6 +589,17 @@
             "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},
+              "format": {"type": "string", "optional": true, "description": "capture image format."},
+              "quality": {"type": "integer", "optional": true, "maximum": 100, "description": "jpeg quality."}
+            },
+            "description": ""
+          },
+          {
             "type": "function", "name": "callback", "parameters": [
               {"type": "string", "name": "dataUrl", "description": "A data URL of a JPEG encoding of the visible area of the captured tab. May be assigned to the 'src' property of an HTML Image element for display."}
             ]
