This is the unofficial official answer I found here: Issue 3422 - android - Animated GIF not working in browser - Project Hosting on Google Code
If you want to work around this with your own Android build, you'll need to modify C++ code, rebuild, and
reflash your phone. You'll need to make two fixes to the released sources.
1) edit the function should_use_animated_gif() in
external/webkit/WebCore/platform/graphics/android/ImageSourceAndroid.cpp (around line 217). Return true
to animate gifs.
2) Change setRGBA() in /WebCore/platform/image-decoders/ImageDecoder.h (around line 173) to call
*dest = SkPackARGB32(a, r, g, b);
*dest = (a << 24 | r << 16 | g << 8 | b);
With these changes, gifs will animated correctly on large memory devices like Droid and Nexus One.
There's no code path for animating gifs in arbitrary applications like Gallery, except by rewriting it to host a
WebView modded as described above.