I think the quick fix for this is to move My Albums to a location outside of the other "standard" Windows directories (like Documents, Pictures, Videos, and so on). So, you might stash it under C:\Users\yourname\My Albums. You can pin that location to Windows Explorer (so you don't have to go hunting for it every time). Then I believe you can tell OneDrive to ignore it. (I'm kind of guessing here, because I don't use it.)
You'll have to tell jAlbum what you've done. Pull up Tools > Preferences > Projects, and change the location of Projects directory, either by typing it in by hand, or by clicking the little folder icon on the right and navigating to its new location.
Thank's Jeff. "BTW, the files shown under OneDrive on your PC aren't physically present on your hard drive." Well, Explorer says that they are... (I have a Swedish version, so I'm not sure about the name "Explorer"). When I check "Properies" (again, not sure...) it says my album of 55 pics is about 0,5 GB on my harddrive.
Not sure how OneDrive behaves, but iCloud does something similar. If I look at the properties on its folder, it tells me that the "size" is 55MB, but the "size on disk" is zero. (I have one foot in each world - Win11 desktop, Macbook Air, iPhone - so iCloud is easier for me, even though it's a little flaky.)
In any event, jAlbum certainly isn't putting any files there by itself. The project is in My Albums/Project Name, and the completed album is in My Albums/Project Name/album. There are no other copies anywhere. The album is also on the server (but not the whole project, with all its inputs).
Me (the jAlbum server guy) and David (the jAlbum client guy) are Swedes, but keeping help pages upto date in multiple languages is a huge task, so we're not... And there are unfortunately too few Swedes using jAlbum... RobM is doing a great job keeping the English upto date.