First, don't forget there are two 'main' Library folders; yours and the Systems. As
tacit said, that's where Adobe puts its tuff, not in your Downloads folder (where all other developers do, instead of re-inventing the wheel!).
I'm still not sure what Spotlight is good for, but it certainly is not for finding things. It simply ignores too much. A waste of bits, IMHO.
I am almost completely baffled by your finding anything in the Screen Savers Prefs "folder."
QUOTE
There IT was, NOT in the thumbnails, just resting in the little display window.
I assume the
"IT" refers to the image your friend was seeing? I'll be calling that the "ghost image" from here on out, BTW.
I am going to use my wildest imagination and attempt to translate what I think you mean:
1. You opened the Desktop & Screen Saver Pref Panel (that is the name of the panel, not a path description which normally uses "/" between directory(folder) names).
2. The main part of the window is a panel allowing the selection of installed images for use as Desktop pictures. If you have more than one folder of pictures, you have those listed on the left-hand part of the above mentioned panel.
3. In the right-hand part of the panel are 'thumbnails' of the images in the selected folder.
4. You did not see the 'ghost image' in the 'thumbnails' seen. Whether you can find that particular image relies on your selecting different folders in the left-hand list AND possibly scrolling the 'thumbnail' display.
5. The 'ghost image' was displayed in the small section in the upper, left-hand part of the Pref Panel window. That is always the current image being displayed as your Desktop picture.
If the above is even partially correct, I offer this wildly astounding explanation for the creation of the 'ghost image.':
Your friend or some helpful soul, has activated a Services menu enabling setting the Desktop (including any windows, in whatever state of display [opening/closing/fading/etc.] and position) to be the current Desktop image. I would suggest that he accidentally right-clicked the Desktop just as the Adobe screen was appearing or fading away. If that option is checked, I'd suggest disabling it. 
I didn't even know it existed until searching for this post! 
A second possibility is that another app can do the above and was accidentally activated to create the image.
Since the 'ghost image/window' is simply an image on the Desktop, it will not respond to any attempts to move, close, use or anything else. It's not a 'real' object, it's simply an image, actually just a
part of the image that was the actual Desktop. The largest part of that image, of course, is whatever your friend has as his normal Desktop image, so he would recognize nothing unusual... except for that 'ghost image!' Any other icons he usually has visible (hard drives/folders/apps/alias'/etc.) would still be there and be usable. That's because they were probably exactly where they always were, and were then exactly on top of their image(s) on that new Desktop picture. Thus, if you tried to move/delete any of those items, it would appear that they were still on the Desktop! But what remained would only be the
image of that icon that is now
part of the Desktop picture! Sounds like the makings of a great April Fools trick...
The "fix" was simply to select a different Desktop in the Desktop & Screen Saver Pref Panel. I suggest, however, that you do a thorough search in the several places in that Pref Panel, for that image. If you indeed find the image, I would suggest you delete it... unless this guys is a reely, reely close friend and you want to help his blood pressure next month...
