Preview edits - stop auto-save

Is there a way to turn off Preview’s auto save?

Example: I just opened an image that I wanted to crop, but also keep the original as is. I made the crop and Preview auto-saved this crop as the original.
Undo does get it back, but I don’t always remember to do this before closing the file.
I realize I should try to remember to make a Duplicate before doing any edits but I’d rather it just not do the auto-save.

Am I missing something?

I don’t think you’re missing anything, other than, as you’ve pointed out, making a duplicate before you modify your document.