My argument for the 1st image is because the colors are bright in the 2nd and 3rd examples, they draw attention more whereas in the 1st, a background image being slightly duller doesn't distract from what is in the foreground. That way you can have brighter colors in the plain you're actually traversing, for power-ups, enemies, etc without worrying about it being confused with the background. The foreground should be highlighted and the background should frame it. This is the way things work in the majority of games for exactly this reason but nevertheless, this is just my subjective opinion. I just thought i'd expand on why ^_^