Complex sentence: Windows Live Photo Gallery also supports Windows XP and facilitates viewing any image format supported by the Windows Imaging Component (including HD Photo) on XP, if the appropriate WIC codecs are installed.
Split into simpler sentences: Windows Live Photo Gallery also supports Windows XP and allow the viewing of HD Photo images on the operating system. It also facilitates viewing any image format supported by the Windows Imaging Component on Windows XP, if the appropriate WIC codecs are installed.