Thank you . . . Kathleen Brade and Mark Smith for a wonderfully implemented add-on that does as you stated it would without any surprises or crashes. Finally, someone managed to build a screenshot-er that simply takes a perfect PNG/JPG snapshot and puts it where you tell it to after automatically, properly naming the image in accordance with the url/page title. Couldn't want an app to do it any better than Pagesaver WE!
Haven't tried JPG's yet because historically, PNG takes and renders the best images for such things as a very long website page, and your app completes that task very well, the best I've ever tried so far, and I've tried every available, in-browser screenshot-er app that's come along for many years.
A personal pref on this: Not that you'd mess things up, but I just don't see how this could be improved, its absolutely perfect! - hence, I'm afraid to update since this version simply because it seems like apps, usually through no fault of the creators, just inherently go awry because of browser conflict. So, I'll keep updating Waterfox and leaving this BEAUTY alone until the two become incompatible and I'm forced to update?

THANK YOU BOTH SO MUCH!