Images · guide

How to crop a picture on Mac, and which tool to use

By Alberto Gulotta · Updated 23 September 2026 · 9 min read

There are two answers to how to crop a picture on mac, both already installed, and they do genuinely different things. One edits the photograph in your library. The other edits a file on disk. Choosing the wrong one is how a crop you made for a Christmas card ends up in every album that photo appears in.

So the choice is not about which is easier. It is about what else you want to change. If the picture lives in your Photos library and you want it cropped from now on — a portrait you want tighter, a scan with a wonky edge — Photos is right, and the crop follows the photo everywhere, which is what you wanted. If you need one cropped copy for one purpose and everything else left alone, either duplicate it in Photos first, or do the job in Preview on a copy of the file.

Straightening is on the same screen and worth using. Apple lists three sliders — Straighten, Vertical and Horizontal — plus the Auto button that does both jobs at once. The two beyond “straighten” correct the leaning you get from pointing a camera up at a building or down at a document, which is the fault cropping cannot fix.

What a crop actually costs you. Pixels, and only pixels. The part you keep is untouched — nothing is degraded, nothing is re-encoded on the way. What shrinks is how large the result can be shown before it softens. A 48-megapixel photograph cropped to a quarter of its area is still a 12-megapixel photograph, which is more than enough for a screen and for most prints. Cropping is the cheapest edit there is, right up until you need the part you removed.

Which is why the recovery routes above are the important half of this page. In Photos, an edited photo can be returned to how it arrived. In Preview, the file has changed, and your way back is the Versions browser rather than an undo. Neither is a reason to hesitate — but knowing which one you are relying on is worth the ten seconds before you drag the rectangle.

Every image editor makes the same choice, and one of them shows you the switch. GIMP documents it as a default with a name: “a fairly recent change in GIMP is that by default the image canvas size isn’t changed after cropping”, and there is a Crop Tool option called “Delete cropped pixels” you tick “to make sure the canvas size is also adjusted to the cropped area”. That is the difference this page describes between the two Mac tools, stated as a checkbox: either the cropped pixels are still in the file or they are gone. Before sending a picture you cropped for a reason, it is worth knowing which of the two you did.

The warning about cropping everywhere, the tools, the shortcut, the aspect ratios and both recovery routes are quoted from Apple’s own Photos and Preview user guides, read on 22 August 2026 and listed below. The argument about which tool suits which job, and the note on what a crop costs, are ours.

Not covered here. It will not treat the two Mac crop tools as interchangeable. One changes the photograph everywhere and the other changes a file, and Apple says so.

It will not skip the duplicate step. Apple marks that warning Important, and it is the difference between one cropped picture and a whole library of them.

And it will not recommend an image editor for something both built-in tools already do. What holds instead is simple: the warning about cropping everywhere and both recovery routes are quoted from Apple’s own Photos and Preview user guides, read on the dates this page names.