I don't know if this has been done before, but I've been searching for these pictures as wallpapers and all I can find are small sized images or ones with really saturated colours.
So I decided to rip the images from one of the episodes I have and voilá.
I took these from a 1080p video so they have their original size, they were not stretched or re-sized, just regular 1920x1080 wallpapers.
About the colour, I just added a tiny tiny bit of contrast, it's barely noticeable but makes them look better.
Sailor Moon and all rights belong to Naoko Takeuchi and etc.