Can I sell Royalty Free files on LightRocket?

Yes absolutely. LightRocket allows you to classify your images as either Rights Managed or Royalty Free. This allows potential buyers to filter search results by Royalty Free. Note, however, that if you classify an image as Royalty Free any people or property depicted will need release forms proving you had permission to create a picture for commercial use. You should also make sure you understand the implications of licensing your work as Royalty Free.