diff --git a/b2g/app/b2g.js b/b2g/app/b2g.js
index 210f7a334c8..ac211f0dcdc 100644
--- a/b2g/app/b2g.js
+++ b/b2g/app/b2g.js
@@ -322,6 +322,7 @@ pref("media.fragmented-mp4.gonk.enabled", true);
 pref("media.video-queue.default-size", 3);
 
 // optimize images' memory usage
+pref("image.downscale-during-decode.enabled", true);
 pref("image.mem.decodeondraw", true);
 pref("image.mem.allow_locking_in_content_processes", false); /* don't allow image locking */
 // Limit the surface cache to 1/8 of main memory or 128MB, whichever is smaller.
diff --git a/gfx/thebes/gfxPrefs.h b/gfx/thebes/gfxPrefs.h
index a72c56f943d..21e428655f7 100644
--- a/gfx/thebes/gfxPrefs.h
+++ b/gfx/thebes/gfxPrefs.h
@@ -232,7 +232,7 @@ private:
 
   DECL_GFX_PREF(Once, "image.cache.timeweight",                ImageCacheTimeWeight, int32_t, 500);
   DECL_GFX_PREF(Once, "image.cache.size",                      ImageCacheSize, int32_t, 5*1024*1024);
-  DECL_GFX_PREF(Live, "image.downscale-during-decode.enabled", ImageDownscaleDuringDecodeEnabled, bool, false);
+  DECL_GFX_PREF(Live, "image.downscale-during-decode.enabled", ImageDownscaleDuringDecodeEnabled, bool, true);
   DECL_GFX_PREF(Live, "image.high_quality_downscaling.enabled", ImageHQDownscalingEnabled, bool, false);
   DECL_GFX_PREF(Live, "image.high_quality_downscaling.min_factor", ImageHQDownscalingMinFactor, uint32_t, 1000);
   DECL_GFX_PREF(Live, "image.high_quality_upscaling.max_size", ImageHQUpscalingMaxSize, uint32_t, 20971520);
diff --git a/mobile/android/app/mobile.js b/mobile/android/app/mobile.js
index 7f28a2f18fe..425a3499fce 100644
--- a/mobile/android/app/mobile.js
+++ b/mobile/android/app/mobile.js
@@ -566,6 +566,7 @@ pref("media.fragmented-mp4.android-media-codec.enabled", true);
 pref("media.fragmented-mp4.android-media-codec.preferred", true);
 
 // optimize images memory usage
+pref("image.downscale-during-decode.enabled", true);
 pref("image.mem.decodeondraw", true);
 
 #ifdef NIGHTLY_BUILD
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index 49c07b5add8..088bf263c9d 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -3783,7 +3783,7 @@ pref("image.cache.size", 5242880);
 pref("image.cache.timeweight", 500);
 
 // Whether we attempt to downscale images during decoding.
-pref("image.downscale-during-decode.enabled", false);
+pref("image.downscale-during-decode.enabled", true);
 
 // The default Accept header sent for images loaded over HTTP(S)
 pref("image.http.accept", "image/png,image/*;q=0.8,*/*;q=0.5");