Windows XP users should still use Automatic Updates (must be XP SP2), the size is only 60M. You can also download the CD image. Wow, it's 400M. Of course, this image file includes a series of XP patches and updates, so it's inevitably a bit large.
Official Windows XP SP3 Download Link
Simplified Chinese Version http://download.microsoft.com/download/e/d/9/ed9b7861-4e43-4c62-a007-4e93aa109602/WindowsXP-KB936929-SP3-x86-CHS.exe
English Version http://download.microsoft.com/download/d/3/0/d30e32d8-418a-469d-b600-f32ce3edf42d/WindowsXP-KB936929-SP3-x86-ENU.exe
Traditional Chinese http://download.microsoft.com/download/2/2/a/22a44f8b-2f1b-46a9-940a-cf4099fd1de9/WindowsXP-KB936929-SP3-x86-CHT.exe
Hong Kong Chinese http://download.microsoft.com/download/2/9/0/29008fe5-f699-47d5-ab32-91bae6c548bf/WindowsXP-KB936929-SP3-x86-CHH.exe