Well, this has to end. So this is the solution:
v1: https://www.mediafire.com/?807oawwe9jycbmn
v2 (updated by rob55rod): http://www.mediafire.com/download/ngo6j ... it.package
These are all the image files you have to modify to fully modify the UI (but to modify, for example, archetypes background, you'll need other files).
So, let's see what's inside the v1 .rar:
- Spore_Images.package : If you don't have GA, these are all the files you need. But if you have it, you still need them. If you have GA they will affect the editors.
ALWAYS instal it at Spore Data folder, even if you have GA installed.
- AG_Images.package : The files that modify the rest of things if you have GA. If you don't, you don't need them.
ALWAYS install it at Spore_EP1 Data folder.
v2 contains this:
- UIDevelopmentKit.package : Literally, every UI image in the entire game, part and category icons included. Also updated to work correctly with patch 5.1, meaning no more screwy Cell Stage UI

ALWAYS install it in the Spore_EP1 Data folder.
And, that's all! If you don't use an image, erase it, you'll save disk space.
And if you want an authomathic, easy and fast installer, request it here! You can also request an option to choose what UI to install: viewtopic.php?f=5&t=5269
So, bye and Happy Modding!