you can batch convert pictures in various photo editing applications, it saves having to do a repetitive task on many files.

for the control track I have several templates of slideshow that I made for the book demos. Substituting one of these for your (Cees')control track was easier than making the slideshow from scratch because Cees had only used a couple of panel memories, so it was easier to put 3 commands in rather than load pictures with 14 sets of command creation. A quick track copy and the job was done. The pictures were renamed to the required filenames in another batch operation in another program.

I always look for the easiest way... and your grandkids needed to see themselves in their own show