How to Edit an Image on Mac | Two Built-In Tools Replace Expensive Software

Mac users can edit images using two free, pre-installed applications—Photos for advanced editing and object removal, and Preview for quick markup, resizing, and background removal—no subscription required.

Whether you want to remove a photobomber from a family photo, crop a screenshot for work, or adjust lighting on a portrait, the tools already on your Mac can handle most of it. The Photos app covers serious editing with AI object removal, filters, and tonal adjustments, while Preview handles the quick jobs like resizing, annotating, and pulling out a background. Both are included with every Mac from the 2019 Catalina release through the current macOS 15 Sequoia—no download, no credit card, no subscription.

Photos App: The Full Editing Suite Built Into Your Mac

Photos is where you go when an image needs real work—adjusting exposure, removing distractions, applying filters, or cropping to a specific ratio. It’s designed for photos you already have in your library, but you can import any image and edit it there.

To start: open an image in Photos, then click Edit in the top-right toolbar. You’ll see three tabs: Adjust, Filters, and Crop[5].

What Each Tab Does

• Adjust gives you sliders for brightness, contrast, highlights, shadows, white balance, sharpness, and more. Drag them to see changes in real time.
• Filters applies AI-enhanced looks—vintage, noir, vibrant—with an opacity slider so you can dial back the intensity[3].
• Crop lets you rotate, straighten, and choose from preset aspect ratios like 16:9 or square[1].

Three features in Photos make it genuinely powerful for a free tool. Auto Enhance is the wand icon that instantly optimizes exposure and color with one click[3]. Object Removal (macOS 12+) lets you highlight a person, sign, or branch and the AI deletes it—adjust the brush size if the selection wraps around your target[3]. And Copy Edits lets you apply the same adjustment batch to multiple photos: press Command-Shift-C on one edited image, then Command-Shift-V on others[3].

To compare your changes against the original, hold the M key or click Show photo without edits[3][5]. When you’re done, click Done—the original is preserved, so you can revert anytime via Revert to Original in the toolbar[1][5].

Preview App: The Quick Editor for Markup and Resizing

Preview is faster and lighter when you don’t need the full Photos workflow. It handles markup, annotations, resizing, background removal, and color adjustments without importing anything into a library.

Open any image in Preview from Finder, or via File > Open. Click the Markup toolbar icon to reveal the toolset[1].

For background removal, click Instant Alpha, drag over the background area, then press Delete—the background disappears cleanly[1][11]. For resizing, click Adjust Size and set width and height in pixels, inches, or percentage. Custom values and presets are both available[11].

A critical difference between Preview and Photos: File > Save overwrites your original image. Use File > Export instead to save a new version and keep your original untouched[1][11]. This is the most common Preview mistake, and it’s permanent unless you have a backup.

Common Mistakes That Ruin Your Edits

Even with great tools, a few habits can spoil the result. Watch for these:

• Over-cropping. Cropping too tightly around the subject cuts off context and leaves no room for recomposition later. Leave a little breathing room around the edges[9].
• Oversharpening. Sharpness sliders amplify noise, especially in shadows. Apply them subtly and zoom in to check for grain[9].
• Ignoring the histogram. Clipped shadows (flattened blacks) and blown highlights (pure white patches) mean lost detail. Keep the histogram’s information within the visible range[9].
• Overwriting the original in Preview. Always Export a new file. Save overwrites; Undo won’t help you once the window closes[1][11].

Third-Party Options When You Need More

Photos and Preview cover most needs, but if you outgrow them—layers, RAW processing, batch editing—these alternatives are worth considering. Free options work well for hobbyists; paid ones pull ahead for professionals.

Install only from official sites—download GIMP from gimp.org, Pixelmator Pro from the Pixelmator Pro official page, and Darktable from darktable.org. Pirated versions carry malware risks and no support[2][6].

Final Setup: Pick Your Primary Tool

Your decision comes down to what you edit and how often. For occasional cropping, annotation, or resizing of screenshots and downloaded images, Preview is the fastest path with no setup. If you regularly edit photos from a phone or camera—adjusting exposure, removing objects, applying consistent edits across batches—the Photos app handles it all for free. Only step to third-party software when you need layers (GIMP or Pixelmator Pro) or professional library management (Lightroom or Capture One). Either way, the two tools already in macOS will save you a subscription fee and keep your first edits simple.