I am trying to crop some photos and would like to keep the original aspect ratio, but the selection tool only has the following options: rectangular, oval, lasso, and smart lasso. The rectangular has only two options; free form or square by holding a shift key.
MacBook Pro (M1, 2020)
What you see on the markup toolbar is what you get. Try the option key as you use click and drag a rectangular selection, and while still selected, work with the visible grips to adjust the selection size. Alternatively, there is the tools menu > Adjust Size… where you can adjust the image ratio proportionately or individually.
You may also need a third-party application instead of Preview to achieve your fixed ratio selection.
I also have a Zsh script that I wrote in 2021 that allows you to enter the aspect ratio (e.g. 1:1.44) and then uses Apple's sip utility to output a new image in that aspect ratio. It is designed to recursively process a folder of images and may require changes for your intended usage.
Is there a way to make a fixed ratio selection in Preview?
