With the addition of Smart Previews in Lightroom 5, Lightroom got some Catalog Settings updates (PC: Edit>Catalog Settings, Mac: Lightroom>Edit Settings).
1) The first is Previews now has information on Total Size of the preview folder. If it’s large, you’ll get a spinning circle while it updates. 2) As Smart Previews get stored in package/folder too, you get a size for them also.
