>>>>>Might be interesting to preface your code above with CLEAR RESOURCES, see if it makes any difference.
>>>>
>>>>Testing as we speak. Just to note that the memory consumption was flipping between 18 and 20 M when it launched. But then I don't remember what it used to be - should perhaps run the old version for a while. Last I remember it displayed about 40000 images before I stopped it, and then the next day the system was unstable. We'll see. I'll run this to a similar number and see what happens.
>>>
>>>After a whole day, it's still getting down to 22M, depending on the size of the currently displayed images (runs separate forms for each monitor). But then I don't think it caused trouble previously either. At one image every 4 seconds it has clicked 20900 so far... though there should have been more. And it wasn't getting any new images to detect, measure up and store in the tables... perhaps that's what's troubling, as I probably have to use the iPicture interface to measure the width and height of each so I can know their orientation (right monitor is upright, so portrait shots are sent there). Perhaps that's the cause...
>>
>>Just out of interest - in the long run (literally) did it make any difference?
>
>Dunno... it didn't use much memory before, doesn't use now, and it doesn't grow. Presently it's again running for about a day (ticked 20500 images shown) and still falls below 20M at times. OTOH, the mentioned behavior (when hovering mouse over the start menu and it looks like it clicks everything it goes over, many of those several times - so I get dozens of explorer windows showing various fake folders (aka "libraries") etc has happened again in a session where I didn't run this screen savior at all. So I can exclude it from the list of suspects. I guess it's the Virtualbox guest additions which flake out from time to time. Which is no big deal - even as a seasoned programmer I can't even imagine what is involved in writing such a huge piece of software. The parts they took from Qemu et al don't make it much easier, as these may contain their own kludges to worry about. Considering what it does, it does it near perfectly.

It's not easy trying to Google something like that. About 95% of the hits are the scenario of running an Ubuntu guest on a Windows host, rather than vice-versa.

Generally for this sort of thing it helps to keep things as bog-standard as possible, and avoid any third party drivers or utilities, or configuration customizations. For example, on Windows hosts I like to use the Microsoft Mouse and Keyboard Center suite so I can remap my mouse's wheel click as a double click. If you have anything like that on either the host or the guest you could test with it disabled.

I was going to suggest testing with the guest additions disabled in the Windows guest but that's probably too much of a PITA. AFAIK you can't disable just the mouse additions while leaving the keyboard, video, seamless integration/shared clipboard etc.