MacOS – How to open images in Preview at full size

I would use Terminal commands slightly different from @Bart's above, although those work just fine.

To disable Preview's default print scaling:

defaults write com.apple.Preview PVImagePrintingScaleMode -bool false

To restore Preview's default print scaling:

defaults write com.apple.Preview PVImagePrintingScaleMode -bool true 

That way, the default stays in Preview's plist, so I don't need some external reminder about that default if I'm poking into it next year when I've forgotten I did this.

Incidentally, the first time I started up Preview after disabling its print scaling, it seemed to hang on launch, so I force-quit and then tried again and it was fine.

Hmm. Tried to edit to make the code lines show...

Ok, here's what you need to do:

1. Open up the first PNG image in Preview. Make sure the side bar is showing.

   

2. Open the second image in Preview, and from the sidebar, drag the thumbnail image from the second window to the first window's sidebar.

   

3. Now, you'll notice that the title bar says "2 documents, 2 total pages." Continue dragging images into the first image until all the images are combined into one PNG. Make sure you save it. :-)