Performance: Large Images

If you have a 640 x 640 sprite, would it improve performance to reduce it 320 x 320 image using an external editor, importing it to Construct, and resizing it once again to 640 x 640 (making it pixelated) within Construct? Or does it not make a difference since you are rendering a 640 x 640 sprite in the end?

You can reduce it inside C2.

No big difference if the quality low or high the size is the matter, and don't forget to crop your images inside C2 to delete the transparent space.

Thanks for the clarification.