I hope I am interpreting you correctly. You are saying that you have some pictures from a portfolio already on your hard drive that you have imported off of a CD and you want to put it on another CD, but the blank disk won't show up on the Desktop, right? If that is your problem, try the following solutions, but if I misunderstood you, I'm sorry, and could you re-explain it?
-Do you have the box checked under Finder>Preferences>General>"Show these items on the Desktop:">"CDs, DVDs, and iPods"? If that's not checked, it won't show up on the Desktop.
-Also, check under System Preferences>CDs & DVDs and see what action you have selected for "When you insert a blank CD:" If you have "Ignore" selected, that's your problem.
-If both of those don't work, and it's still not showing up, try going into Disk Utility, and see if you can see the disk on the left. If you can see it (it might have a weird name like disk/rev/1 or something like that, or it might not, I'm not sure), select it and try hitting "Mount" at the top.
-If none of these methods work, then you may have a problem with your drive. Try cleaning it, if you have a disk cleaner.