I just thought of a solution without changing the script, I don't know why I did not think of it before, just change the name of the images, instead of calling it "ticketnr1.jpg", call it something like "76554449.jpg".
That way if anybody looks at the source code it will not tell them exactly what the number is.
I am still interested hearing if there is a different way just using flat files.
We might do more raffle draws in the future so it will be a handy tool.