--- a/browser/modules/WindowsPreviewPerTab.jsm
+++ b/browser/modules/WindowsPreviewPerTab.jsm
@@ -67,18 +67,24 @@ XPCOMUtils.defineLazyServiceGetter(this,
 XPCOMUtils.defineLazyServiceGetter(this, "imgTools",
                                    "@mozilla.org/image/tools;1",
                                    "imgITools");
 XPCOMUtils.defineLazyServiceGetter(this, "faviconSvc",
                                    "@mozilla.org/browser/favicon-service;1",
                                    "nsIFaviconService");
 
 // nsIURI -> imgIContainer
-function _imageFromURI(uri, callback) {
+function _imageFromURI(uri, privateMode, callback) {
   let channel = ioSvc.newChannelFromURI(uri);
+  try {
+    channel.QueryInterface(Ci.nsIPrivateBrowsingChannel);
+    channel.setPrivate(privateMode);
+  } catch (e) {
+    // Ignore channels which do not support nsIPrivateBrowsingChannel
+  }
   NetUtil.asyncFetch(channel, function(inputStream, resultCode) {
     if (!Components.isSuccessCode(resultCode))
       return;
     try {
       let out_img = { value: null };
       imgTools.decodeImageData(inputStream, channel.contentType, out_img);
       callback(out_img.value);
     } catch (e) {
@@ -87,21 +93,21 @@ function _imageFromURI(uri, callback) {
       let defaultURI = faviconSvc.defaultFavicon;
       if (!defaultURI.equals(uri))
         _imageFromURI(defaultURI, callback);
     }
   });
 }
 
 // string? -> imgIContainer
-function getFaviconAsImage(iconurl, callback) {
+function getFaviconAsImage(iconurl, privateMode, callback) {
   if (iconurl)
-    _imageFromURI(NetUtil.newURI(iconurl), callback);
+    _imageFromURI(NetUtil.newURI(iconurl), privateMode, callback);
   else
-    _imageFromURI(faviconSvc.defaultFavicon, callback);
+    _imageFromURI(faviconSvc.defaultFavicon, privateMode, callback);
 }
 
 // Snaps the given rectangle to be pixel-aligned at the given scale
 function snapRectAtScale(r, scale) {
   let x = Math.floor(r.x * scale);
   let y = Math.floor(r.y * scale);
   let width = Math.ceil((r.x + r.width) * scale) - x;
   let height = Math.ceil((r.y + r.height) * scale) - y;
@@ -431,17 +437,17 @@ TabWindow.prototype = {
     let docShell = this.win
                   .QueryInterface(Ci.nsIInterfaceRequestor)
                   .getInterface(Ci.nsIWebNavigation)
                   .QueryInterface(Ci.nsIDocShell);
     let preview = AeroPeek.taskbar.createTaskbarTabPreview(docShell, controller);
     preview.visible = AeroPeek.enabled;
     preview.active = this.tabbrowser.selectedTab == tab;
     // Grab the default favicon
-    getFaviconAsImage(null, function (img) {
+    getFaviconAsImage(null, this.win.gPrivateBrowsingUI.privateWindow, function (img) {
       // It is possible that we've already gotten the real favicon, so make sure
       // we have not set one before setting this default one.
       if (!preview.icon)
         preview.icon = img;
     });
 
     // It's OK to add the preview now while the favicon still loads.
     this.previews.splice(tab._tPos, 0, preview);
@@ -530,17 +536,17 @@ TabWindow.prototype = {
         this.enabled = true;
         break;
     }
   },
 
   //// Browser progress listener
   onLinkIconAvailable: function (aBrowser, aIconURL) {
     let self = this;
-    getFaviconAsImage(aIconURL, function (img) {
+    getFaviconAsImage(aIconURL, this.win.gPrivateBrowsingUI.privateWindow, function (img) {
       let index = self.tabbrowser.browsers.indexOf(aBrowser);
       // Only add it if we've found the index.  The tab could have closed!
       if (index != -1)
         self.previews[index].icon = img;
     });
   }
 }