The directions is in the manual.
You have to create a folder called PICTURES
and the file size of the disc must be bigger than 100mb or something like that.
so just put in some junk files in a different folder on the disc.
Dont put mp3s, cuz it will read the mp3s and it wont read the PICTURES folder!
I also had a little bit of trouble doing this. In my situation it turned out that I was forgetting to format the disc for use with other programs. I also made the mistake of not ensuring that the folder was the correct size (MB). Make sure you fill your folder with some extra pictures even if you don't want to use them.