diff --git a/browser/base/content/browser-textZoom.js b/browser/base/content/browser-textZoom.js
index 1d1ffbf22e22..d947ebdd359d 100644
--- a/browser/base/content/browser-textZoom.js
+++ b/browser/base/content/browser-textZoom.js
@@ -327,17 +327,19 @@ var FullZoom = {
    * one.
    **/
   _applyPrefToSetting: function FullZoom__applyPrefToSetting(aValue, aBrowser) {
+    var browser = aBrowser || gBrowser.selectedBrowser;
+
     if (!this.siteSpecific || gInPrintPreviewMode ||
-        content.document instanceof Ci.nsIImageDocument)
+        browser.contentDocument instanceof Ci.nsIImageDocument)
       return;
 
     try {
       if (typeof aValue != "undefined")
-        ZoomManager.setZoomForBrowser(aBrowser || gBrowser, this._ensureValid(aValue));
+        ZoomManager.setZoomForBrowser(browser, this._ensureValid(aValue));
       else if (typeof this.globalValue != "undefined")
-        ZoomManager.setZoomForBrowser(aBrowser || gBrowser, this.globalValue);
+        ZoomManager.setZoomForBrowser(browser, this.globalValue);
       else
-        ZoomManager.setZoomForBrowser(aBrowser || gBrowser, 1);
+        ZoomManager.setZoomForBrowser(browser, 1);
     }
     catch(ex) {}
   },
diff --git a/browser/base/content/test/browser_bug386835.js b/browser/base/content/test/browser_bug386835.js
index f0d1ae3b4e88..17f12925315f 100644
--- a/browser/base/content/test/browser_bug386835.js
+++ b/browser/base/content/test/browser_bug386835.js
@@ -1,4 +1,5 @@
 var gTestPage = "http://example.org/browser/browser/base/content/test/dummy_page.html";
+var gTestImage = "http://example.org/browser/browser/base/content/test/moz.png";
 var gTab1, gTab2, gTab3;
 var gLevel;
 
@@ -44,13 +45,23 @@ function thirdPageLoaded() {
   zoomTest(gTab2, gLevel, "Tab 2 should be zoomed now");
   zoomTest(gTab3, gLevel, "Tab 3 should still be zoomed");
 
+  load(gTab1, gTestImage, imageLoaded);
+}
+
+function imageLoaded() {
+  zoomTest(gTab1, 1, "Zoom should be 1 when image was loaded in the background");
+  gBrowser.selectedTab = gTab1;
+  zoomTest(gTab1, 1, "Zoom should still be 1 when tab with image is selected");
+
   finishTest();
 }
 
 function finishTest() {
   FullZoom.reset();
   gBrowser.removeTab(gTab1);
+  FullZoom.reset();
   gBrowser.removeTab(gTab2);
+  FullZoom.reset();
   gBrowser.removeTab(gTab3);
   finish();
 }