Broken up into several ZIP files, one file per movie/OVA:
5 Centimeters Per Second Wallpaper Collection - 277 Wallpapers.zip Bosporus Kaikyou Tunnel Wallpaper Collection - 4 Wallpapers.zip Children Who Chase Last Voices Wallpaper Collection - 115 Wallpapers.zip Dareka no Manazashi Wallpaper Collection - 10 Wallpapers.zip The Garden of Words (Kotonoha no Niwa) Wallpaper Collection - 437 Wallpapers.zip The Place Promised in Our Early Days Wallpaper Collection - 58 Wallpapers.zip Voices of a Distant Star Wallpaper Collection - 8 Wallpapers.zip
(Once again, since people like to complain about this: The vast majority of the images in the ZIP files are high-quality 1080p screenshots. If you don't like to use screenshots as wallpapers, this wallpaper collection probably isn't too relevant to your interests.)