http://www.boardgamegeek.com/article/3530448

But which is which? Have you replaced the existing cubes with MegaCubes or MicroCubes? Enquiring minds need to know and there is no ruler or other measuring device in the image so we can determine

The answer to your question, from the linked article:

Which would mean the smaller cubes are the replacements for the larger cubes

Sorry, I probably should have been more clear. The big wooden cubes on the left come with the game. The little polymer clay ones on the right are the ones I made.