Preview app automatically saving changes?

This is a change you can make globally, not on a per application basis.

If you want the old way, whereas a file is not automatically saved, go to System Preferences->General, and CHECK

"Ask to keep changes when closing documents".

VikingOSX wrote:

The moral from this is that you change copies of original images in Preview, and now, use /Applications/Time Machijne to restore the original image.

Now I see. My moral of the story is I always close any open Preview windows before I quit Preview which brings up…

FWIW, I resented this change when it appeared over a decade ago, but then came to embrace it.

You can always revert, you know?

File->Revert to->Browse All Versions

even without having used Time Machine in the interim.

I don't have my Time Machine drive connected this morning.

I deliberately added an annotation to the image I posted above, then did File->Revert to->Browse All Versions:

Apple's Preview has had autosave for several iterations of macOS over the years. And your adjusting a current image in Preview will automatically apply those changes to the current image, even if the image icon on the Desktop does not appear to change.

Initially, I performed a Get Info window on a 300 dpi 512x512 PNG (copy) on my Desktop. Then I opened it in Preview, selected Tools > Adjust Size, and with Scale proportionally and Resample image selected, set the image dimensions to 256, and clicked OK to make the change. Though I observed no visual PNG icon change on the Desktop, the Get Info image dimensions immediately changed from 512x512 to 256x256 when I clicked OK on that Adjust Size panel.

Using macOS 12.4 on a 2021 16-in MBP M1 Pro.

The moral from this is that you change copies of original images in Preview, and now, use /Applications/Time Machijne to restore the original image.

You may be able to recover the old version from backup. You do have Time Machine, right? Even if there was no recent backup to your external drive, a local snapshot may save you.

Open the document, and do File->Revert To->Browse All Versions.

I just did this as a test and it worked perfectly.

tiagorocha wrote:

That doesn't work for me... making a change to a file, whether I close the window after that or not, will apply the change automatically. I'm on Catalina 10.15.7

This is weird that some people experience something different than me.

Sorry about that. I have "Ask…" enabled for so long I don't even think about it.

That should not happen unless you hit Return on this screen.