Hi Gene,
I am a newbie and may be incorrect in my explanation of this

, but I have been reading three audio mags, and audiogon for about a year,and I have heard this a bit in my first set up.
This is my interpretation, so others can feel free to correct me. (as I may be talking out my A##)

Soundstage, would be like your sitting in the audience, and starring at the stage, it may be 20 0r 30 feet across depending on the stage.
This is why you separate speakers 6 to 8 feet apart, so you have a nice width of soundstage. I have heard that many speakers that have good soundstage will project the stage beyond, right and left ,and even behind the speakers.In a good soundstage you should also have depth, so you can hear that the bass player, is say ,standing 5 feet behind the singer and the drummer may even be heard a few feet behind the bass player.
Imaging as I understand, is being able to close your eyes and pinpoint the exact location of each instrument on stage.(left ,right,center)
I understand that bookshelf speakers usually are better at doing both of these things then floorstanders, I am sure that good floorstanders are very capable of this as well. I also understand that set up has alot to do with this.
I would appreciate any sp techers or any one else with experience to correct or elaborate on this ,as this could be very informative for me and other newbies.
So ,SP Tech owners : How do the Minis image and soundstage? Is this one of there great attributes? I have heard alot about their timbrel accuracy, and great base, and musicality.
Thanks,
Todd