Then I found some information from MaxisAndrew back in 2008, they state that this was intentional:
What is shown in the first two images in this thread is not a bug or driver or graphics issue. It is pretty much as designed.
Spore as a game is all about creating your own content. When you are in the editors, and almost nothing else is being displayed, we can show you the full model you are working on, with individual full-resolution textures for every little part that makes it up. In the editors you are seeing the original source data.
When you view the final model in game (or in the Sporepedia, which uses the in-game model), you see what we call a 'baked' version of your original model. This is an optimized version of the model so that we can display many of them at once (including many different types of model), plus the planet, plus the trees, and so on. The graphics constraints in-game are much much more severe than those in the editor.
These optimizations include: welding all parts and animations into a single continuous mesh, generating four LODs with varying vertex counts, collapsing all the source textures into one texture page for faster rendering, and compressing those textures. (Really, on high end systems there are two to three pages, including diffuse, normal map, and specular info.)
All of this has to happen in the background within a couple of seconds, both as you exit back to the game, and also as other people's creations are pollinated into your game. This is non-trivial.
The texture packing and resampling is why the textures you see do not match the original ones in the editor. Although there may be improvements to the process over time, we are never going to be able to match what you see in a more standard game where the model textures are pre-authored as single hand-packed sheets by skilled artists.
Does anyone here think they can make a change on this? Rather than using the 'baked' creations in-game and in adventures, they use the originals from the editor instead? It would be a massive change to Spore's quality, despite it being slow for potato computers... We're in 2018 now, hardware eventually catches up.
I've also been messing around with a few numbers in the configuration file, you can make your creature very shiny, multicolored, basically a lot different from the original. These actually transfer into GA's editor and in-game. Thread here: http://forum.spore.com/jforum/posts/list/87074.page