Dreamtime introduced autopopulating title, description and keywords from a previous image (it remembers the last 5)
Now by popular demand they have tweaked their system so it will autopopulate the categories as well
AND you can just get the categories from a previous image but do that first before you change the other data as when it retrieves the categories the rest of the data reverts to the IPTC data.
Well if they don't want to scrap categories at least it nice to see they are making entering categories easier.