I've got ver4, I think the latest is ver5, but I'm pretty sure that what you thought you saw wasn't a quick background change, Image Zone has a
very basic set of editing tools, color adjust, saturation, crop, rotate etc. no in depth editing tools. It does have a project center, creating cards, calendars flyers etc.. it might have been that you caught a glimpse of one of these features, the cards for instance. sveral different templates and card backgrounds that add the complete photo to a background, not a background replacement of the photo itself, granted it does these in a single click
Now it's entirely possible the latest version has some newer features, so I can't say with 100% certainty that it doesn't have what you describe. I'll defer to someone who has it.
I don't really use it (Image Zone) much, I find it to be a big resource hog. It came bundled with printer software. I prefer to edit with other software and as I use my own server to host files, the photo sharing portion doesn't hold much use for me.
hope this helps
Chester