How to Resize photos

If you want to resize while in macOS, do this:

Navigate to the image (either using the Finder, or on your Desktop).

Double click on the image – this should open the image in Preview, if it doesn’t, close it and right click to choose Open With and select Preview.

Click on Tools.

Choose Adjust Size.

On iPhone:

https://www.iphonelife.com/content/how-to-resize-photos-iphone-cropping-to-specific-ratio

To reduce the photo in the iPhone itself.

To reduce the photo in the Mac: Open with Preview > Markup > Rectangular Selection to crop to whatever size, if that is what you want, then click on the crop icon that appears.

But, if you want only to resize the photo in the Mac: Preview > Tools > Adjust size.

You can also first crop the photo and then resize. Of course save the result.