Yes, pretty much what I was thinking. Thanks for the confirmation. May as well post a totally new version as you'd have to update the links in forums anyway.  Of course it depends what the reason for the new version was, if there was a fault with the old one, only just recognised, then I'd rather replace the faulty version entirely, but if it's just an improvement, or an adjustment to the tone or a colour adjustment, then the old one isn't really faulty.  Then I'd leave the old one there.

I've already done that with an image of snowy footprints - I left the old one, the original version where the snow was rather greyish in tone, I left it up there, as that's the way it looked on that day, but I also brightened it up a bit and posted that version with the snow looking a bit whiter, both versions are perfectly useable, in fact I've used the original version for a grayer toned image - like on a dull day, or towards evening, and the whiter version for a brighter day, or at least, a brighter scene.