How to Merge Two Screenshots into One Image on Mac

To merge two screenshots into one image on a Mac, use Preview for a one-off composition with manual placement, or Shortcuts when you want a repeatable horizontal, vertical, or grid workflow. Preview gives you more control over canvas size and alignment; Shortcuts is faster for the same operation repeated across many files.

How to put two screenshots side by side in Preview

Preview is built into macOS and works well when the two images need different positioning, cropping, or canvas dimensions.

1. Put both screenshots in one folder. Give them clear names such as left.png and right.png.
2. Open the first screenshot in Preview. If macOS opens images in separate windows, open the first file directly and keep it as the base image.
3. Show the thumbnail sidebar. Choose View > Thumbnails. Apple’s Preview guide documents that image files can be added to an open document by dragging them into this sidebar.
4. Add the second screenshot. Drag it into the thumbnail sidebar, or open it and copy its image contents before pasting into the first document.
5. Make the canvas wide enough. For side-by-side placement, the canvas needs room for both image widths plus any gap you want between them. If the screenshots have the same height, use that shared height to avoid empty vertical space.
6. Position the images. Use the thumbnail order and the canvas to place the first image on the left and the second on the right. Keep both at the same scale when you want a clean seam.
7. Export the result. Choose File > Export, then select PNG for crisp interface text or JPEG when a smaller file matters more.

Preparing a clean side-by-side layout

• Crop browser chrome, blank margins, and unrelated notifications before combining the screenshots.
• Match the screenshots’ pixel dimensions when possible. Different heights create an uneven bottom edge or empty canvas.
• Leave a small, consistent gap if the screenshots contain similar panels and a seam would be difficult to read.
• For documentation, align the top edges first; for before-and-after comparisons, align the most important content rather than the window edges.

How to combine screenshots vertically into one long image

The same Preview workflow works for a vertical stitch, such as two consecutive sections of a webpage.

1. Open the first screenshot and display View > Thumbnails.
2. Add the second screenshot to the document.
3. Make the working canvas tall enough for both images. The combined height is approximately the first image height plus the second image height, minus any overlap you intentionally remove.
4. Place the second screenshot directly below the first. Match the left edges and keep the scale identical.
5. Check the join at 100% zoom. Repeated content, a doubled header, or a one-pixel shift is easier to spot before export.
6. Export as PNG or JPEG from File > Export.

When the screenshots overlap

If both screenshots include the same page area, crop one image so the shared section appears only once. Use a distinctive line, heading, or image as the alignment point. Avoid stretching either screenshot to force a match; resizing changes text sharpness and makes the seam more visible.

Use Shortcuts to combine screenshots repeatedly

Shortcuts is the better choice when you regularly combine screenshots or want a Finder-triggered action.

1. Open Shortcuts and create a new shortcut.
2. Add an action that selects or receives multiple image files. You can configure the shortcut to accept images from Finder or prompt for files when it runs.
3. Add Combine Images.
4. Choose Horizontally for a side-by-side result, Vertically for a long image, or the grid option when combining more than two screenshots.
5. Set the spacing or other available layout controls to match your intended seam.
6. Add Quick Look if you want to inspect the combined image before saving it.
7. Add a save or export action and select the destination folder and image format.

Run the shortcut from the Shortcuts app, Finder, a keyboard shortcut, or a Quick Action trigger after configuring that entry point.

Shortcuts workflow for a two-image vertical stitch

Receive images from Finder
→ Combine Images: Vertically
→ Quick Look (optional)
→ Save File to a chosen folder

Preview or Shortcuts: which method should you choose?

Need	Best choice	Reason
One carefully positioned composition	Preview	Manual canvas sizing, cropping, and placement
Repeated side-by-side or vertical merges	Shortcuts	A saved action reduces the same steps each time
Several screenshots in a grid	Shortcuts	The Combine Images action can arrange multiple inputs
Different image sizes that need hand alignment	Preview	You can adjust the canvas and placement interactively
No paid software	Either	Both are included with macOS

Image quality, dimensions, and file format

• Use the original files. Avoid taking a screenshot of a screenshot; each extra resampling step can soften small text.
• Keep one scale. If one source is a Retina capture and the other is not, their apparent text size may differ even when the browser view looks similar.
• Prefer PNG for interfaces. PNG preserves sharp text, lines, and diagrams. JPEG can produce a smaller file for photographic content but may add compression artifacts around text.
• Check the final pixel size. Extremely tall images may be awkward to preview, upload, or embed. A PDF can preserve selectable text better when the content is a long document, although the requested output here is one image.
• Keep orientation consistent. Two portrait screenshots usually combine more naturally vertically; two landscape screenshots usually work better side by side.

Troubleshooting merged screenshots on Mac

Problem	Likely cause	Fix
The second image is not visible	It was opened in another window instead of added to the document	Show View > Thumbnails and drag the file into the sidebar, or copy and paste the image contents.
The join has a white strip	The canvas is larger than the combined image bounds	Reduce the canvas or place both images against the same edge before exporting.
The screenshots have different text sizes	Different Retina scale or source dimensions	Capture both at the same display scale, or resize one before combining while preserving its aspect ratio.
The vertical result repeats part of the page	The source screenshots overlap	Crop the duplicate section from one image and align using a unique visual landmark.
Shortcuts combines files in the wrong order	Finder selection order is not the visual order you expected	Rename files with numeric prefixes such as 01-top.png and 02-bottom.png, or inspect the input order in the shortcut.
The exported file looks blurry	It was scaled down or saved with lossy compression	Keep the source pixel dimensions and export PNG when sharp text matters.
The file is too large to share	A tall PNG contains many high-resolution pixels	Crop unused margins, reduce dimensions for the destination, or export JPEG when photographic compression is acceptable.

Or skip the browser setup

If the screenshots you need are web pages rather than local image files, ScreenshotNeo can capture the source pages for you before you combine them in Preview or Shortcuts. It returns a PNG, JPEG, WebP, or PDF from one GET request. See the ScreenshotNeo API documentation for the full request options.

curl -G "https://api.screenshotneo.com/v1/shot" -d access_key=YOUR_API_KEY --data-urlencode url=https://stripe.com -o shot.webp

import requests
r = requests.get("https://api.screenshotneo.com/v1/shot", params={"access_key": "YOUR_API_KEY", "url": "https://stripe.com"}, timeout=90)
open("shot.webp", "wb").write(r.content)

const q = new URLSearchParams({ access_key: 'YOUR_API_KEY', url: 'https://stripe.com' });
const res = await fetch(`https://api.screenshotneo.com/v1/shot?${q}`);

Cookie banners, newsletter popups, and chat widgets are removed before the shot. Bot checks, blank pages, failed loads, timeouts, and cache hits are not billed, and the response identifies the page verdict and billing status in headers. ScreenshotNeo also provides an MCP server so AI agents can take screenshots, plus full-page capture, CSS selector capture, custom viewport and device settings, waiting controls, custom CSS and JavaScript, and PDF output. The free plan includes 1,000 screenshots each month with no card; paid plans start at $5 for 3,000 shots.

Create a free ScreenshotNeo account and start with the 1,000 included screenshots.

FAQ

Can I merge screenshots without installing an app?

Yes. Preview and Shortcuts are included with macOS, so both workflows use built-in tools.

What is the fastest way to make a long screenshot?

For occasional work, place images vertically in Preview. For repeated work, save a Shortcuts action with Combine Images set to Vertically.

Should I choose PNG or JPEG?

Choose PNG for interface text and diagrams. Choose JPEG when a smaller file is more important and some compression is acceptable.

Can Preview automatically stitch a scrolling webpage?

The workflow here combines existing image files. To capture a complete webpage in one operation, use a browser’s full-page capture feature or a screenshot API, then edit or combine the resulting files if needed.