jAlbum is creating a very large album - nearly 1 GB. I have many large originals and they are not scaled down. in an effort to shrink the size, I selected Link to scaled-down images only in Settings > Pages and Force ReMake as well as Make Test. The processing is done in a split second. The size of images in the sub-folder under Album are the same as in the folder where originals are stored. I see no shrinkage.
The scaled images will be found in the album/slides directory, not directly under album, which is where the originals land if you're including them in the album. And also, under Tools, Preferences, Album, check Synchronize output directory.
As always, do not choose Process only updated subdirectories. Changing linking choices or image bounds does not "update" a subdirectory.
ETA: Edited to correct a wrong statement.
ETA: And if you've just changed to Synchronize output directory, you might have to force the issue by deleting the local album, the making it again.