Edit3 kills slideshow image display

I was going to edit slideshow, but I ran into a more fundamental problem.

If I open slideshow.php with edit3, then save slideshow.php without making any changes, then put this into the Scholar Theme, the slideshow no longer shows the images, but the text displays just the same as before.

If I put the original slideshow.php back into Scholar, slideshow works fine. I can repeat this with the same results.

What could edit3 possibly be doing with only a file open followed by a file save, that could cause this?

I suppose you can test this on your end also to see if you get the same result.