I'm not sure what you are asking, when you say "disk" do you mean a hard drive as BobbyG suggests, or are you talking about burning to a CD/DVD?
Archival preservation is a big topic, but it is always wise to have a back-up copy of any magnetically stored data. There is some argument about the storage stability of optical discs but I think most of that centers around the physical and file formats. For instance, if you archive something to a CD in 1999...will there still be CD players 30 years later? Will .jpg still be a recognized file format?
IMO the best thing is to copy them to your hard drive, and back up a copy onto an external drive as Bobby suggests. If you have time, you could also burn hard copies to CD/DVD.