Mara,

Optical devices will roll over and die with no warning.
Try your disks in another system. If your Pics can be seen then your device has stoped working. From your post I believe that your optical device has stoped working and would suggest trying this first.

Depending on how the files where burned may also cause an issue. Leaving the disks open to allow files to be added
has created issues. One solution that has been offered has been to close the disks.

Their are third party utilites that will pull data from CDs'. The one I use is out of business and I will not recommend one that I have not used. Other will join and list the application they use.