IMPROVEMENT: refactor ImageExists and SetupImage
ImageExists should just check the existance of the image and should not set it if image is found, we should have another function for that.
ImageExists should only get pack as copy and not as ref.
SetupImage is currently an utils of pack, but now it becomes more and more a class method, this should be changed.
Suggestion:
pack.ImageExists: check if the image exists in the setup image registry pack.SetupImage: make sure the image is available for running/exploring (check existance, load archive, rebuild)
add some utils like loadArchive? lookForImage? ...