3. Can you delete files from a CD-R? Or if I put in a CD-R that isn’t blank and don’t realise will it overwrite the files already on the disk or add to them?
No, and no. The only PC burning program I use is "mgBurm". Once you name the CD and hit "burn", you're committed. It, (and to the best of my knowledge, other programs), automatically "finalize" the disc. You can't change your mind,and CD-R cannot be erased or overwritten.
If your program is asking you to "name" the disc, the chances are that the information is in the queue, and not on the disc.(yet).
There's as easier way to figure these things out. Just right click on the disc in "computer" and select, "properties". That should tell you all you need to know about the disc.
As for mixing jpegs and audio files, it depends on the player. Some players will reproduce.images. But as for mixing file types, I think that might get a bit dicey.
As for all the anxiety this is causing you, you do realize CD-Rs are only 20 cents a pop when bought in lots of a hundred, don't you?
Ritek are (mostly my favorites. TDK brand discs are actually Ritek as well.
These are good as well;
FWIW, the only burner that permitted leaving a session "open", was a stand alone CD Music recorder I had, which did ask you if you wanted to "finalize" the disc. Standard CD-R for computer won't work in that type of machine, it only worked with CDs specifically designed for music.