I came across this today. I saw that it was high resolution but lacked color, so I went into Photoshop and changed it up a bit. Ended up with this: Download: https://dl.dropbox.com/u/32146097/Jupitah.rar Simply delete the Jupiter folder in [Space Engine's folder]\Data\Textures\Planets and place the one in the archive in its place.
Good job editing the color and contrast. I personally prefer the original version, but that's just me, it's one of my favorite Jupiter maps. I've never actually used it in SpaceEngine, so I don't know how it looks. Perhaps it would be too washed out by HDR effects. Extra color and contrast would definitely help with that.