The new size limit (for service pack 4) is 2048 x 2048. THERE'S A CATCH, however ... You can only use original photos that are a power of 2. So 512 x 512, 1024 x 1024 or 2048 x 2048 original photos will end up with face textures of that size. BUT, if you use a 2000 x 2000 photo it will go to the next size down, or 1024 x 1024. A 4000 x 4000 photo will go down to 2048 x 2048.