10 Preview Tips Every Mac User Should Know in 2026

Preview is worth a second look. Most people open it to glance at a photo or skim a PDF, then close it without realizing it can batch-resize images, sign contracts, merge PDFs, strip backgrounds, and encrypt files, all without touching another app.

These tips are tested on macOS 26 Tahoe and apply to macOS Big Sur and later.

Resize Multiple Images at Once

This is one of the most useful things Preview can do, and most people never find it. Select a batch of images in Finder, open them all in Preview at once, and resize the whole group in seconds.

1. Select the images you want to resize in Finder.
2. Right-click any one of them and choose Open With > Preview.

3. In Preview, press Cmd + A to select all images in the sidebar.
4. Go to Tools > Adjust Size.

5. Enter the new dimensions and click OK.

Save with Cmd + S and every selected image updates to the new size.

Add a Signature to Any Document

Printing a document to sign it is a relic. Preview handles signatures directly, and once you create one, Apple documents that it syncs via iCloud between Preview and Mail on your other Apple devices, so you don’t have to redraw it every time.

1. Open your PDF in Preview.
2. Click the Markup button (the pen-tip icon) in the toolbar.
3. Click the Sign tool in the Markup toolbar.
4. If you don’t have a saved signature, click Create Signature. You can draw it on your trackpad, capture it with your Mac or iPhone camera, or use one synced from another Apple device.
5. Click your signature to place it on the document. Drag it to reposition, and drag the handles to resize.

That iCloud sync between Preview and Mail is quietly one of the better things about this workflow: create your signature once, and it is there the next time you need it in either app.

Convert Files Between Formats

Preview supports JPEG, PNG, TIFF, HEIC, PDF, and several other formats. Switching between them takes about ten seconds.

1. Open the file in Preview.
2. Go to File > Export.

3. Open the Format dropdown and pick your target format.

4. Click Save.

This works for images. For PDFs you want to keep as PDFs with encryption or different settings, use File > Export as PDF instead; that’s also the route to password protection, covered below.

Password-Protect a PDF

You can protect your confidential files with a password without leaving Preview.

1. Open the PDF in Preview.
2. Go to File > Export as PDF.

3. Check the Encrypt box in the save dialog.
4. Enter a password and click Save.

That PDF now requires the password to open. Keep it somewhere safe. Preview can’t recover it.

Create a New File from Your Clipboard

If you’ve copied an image or screenshot to your clipboard, Preview can turn it into a standalone file right away.

1. Copy an image to your clipboard. For screenshots, press Cmd + Ctrl + Shift + 4 to copy a selection directly to the clipboard rather than saving it to your desktop.
2. Open Preview.
3. Go to File > New from Clipboard.

Preview creates a new document from whatever’s on your clipboard. From there you can annotate it, export it, or convert it to another format.

Combine PDFs by Merging Pages

This is the feature people discover after years of paying for a separate PDF tool. You can drag pages from one PDF into another entirely within Preview.

1. Open one PDF in Preview and enable View > Thumbnails to show the sidebar.
2. Go to Edit > Insert > Page from File and select the PDF you want to add.

3. Drag the thumbnails in the sidebar to reorder pages.
4. Save with File > Save (Cmd + S).

You can also drag a PDF file directly from Finder into the Preview sidebar. Make sure the target document window is active first, or Preview may open it as a new document rather than merging it in.

Remove Pages from a PDF

Sometimes a PDF arrives with a cover page, a duplicate, or a blank at the end you don’t need. Preview handles this cleanly.

1. Open the PDF in Preview with View > Thumbnails enabled.
2. Click the thumbnail of the page you want to remove. Hold Cmd to select multiple pages.
3. Go to Edit > Delete (or press Delete on your keyboard).

4. Save with File > Save (Cmd + S).

Remove Image Backgrounds with Instant Alpha

Preview’s Instant Alpha tool is genuinely underused. For logos on white backgrounds or simple product shots, it actually works well without any extra software. It won’t match Pixelmator Pro for complex subjects, but for solid backgrounds it’s fast.

1. Open your image in Preview.
2. Click the Markup button to show the Markup toolbar.
3. Click the Instant Alpha tool (the magic wand icon).

4. Click and drag across the background. The selection expands to cover similarly-colored areas as you drag.
5. Press Delete to remove it.
6. Export as PNG via File > Export. JPEG doesn’t support transparency, so your removed background reappears as white if you use it.

The more uniform the background color, the cleaner the result.

View EXIF Data for Any Image

Before sharing a photo publicly, it’s worth knowing what’s embedded in the file. Preview’s Inspector shows the full EXIF data: camera model, lens, aperture, shutter speed, ISO, and often GPS coordinates.

1. Open the image in Preview.
2. Go to Tools > Show Inspector (Cmd + I).

3. Click the Exif tab.

The GPS coordinates especially catch people off guard. Worth checking before anything goes online.

Annotate PDFs and Images with Markup

The Markup toolbar is where Preview earns its keep. Click the Markup button (pen-tip icon) in the toolbar to reveal it.

For PDFs, the tools include:

• Highlight / Underline / Strikethrough: select text first, then pick the style from the toolbar
• Note: floating sticky-note comments anchored to a spot on the page
• Text: a box you can drag and resize anywhere
• Shapes: rectangles, ovals, arrows, lines, and callouts
• Sketch / Draw: freehand drawing; Sketch auto-recognizes standard shapes as you draw them
• Sign: place a stored or new signature
• Redact: permanently blacks out content on save

For images, the same tools appear, but with one difference that trips people up. Once you save an annotated image, those annotations are permanently embedded. You can’t move or delete them afterward. If you think you’ll need to adjust annotations later, export the image to PDF first (File > Export as PDF), annotate the PDF version, and keep the original image as a backup.

Saving PDFs with annotations:

• File > Save or File > Export as PDF: keeps annotations editable by you or the next person who opens the file
• File > Print > Save as PDF: flattens annotations permanently; the right choice when you’re sending the final version and don’t want recipients editing your markup

One real limitation to know upfront: Preview annotates around PDF content. It doesn’t let you edit existing text inside a PDF. For that you need a dedicated editor. PDF Expert is the lighter option; Adobe Acrobat does more but costs significantly more. Either one handles what Preview can’t.

Preview is one of those apps that rewards you for looking past the first menu. Most of what’s here takes under a minute and saves real time the next time a contract lands in your inbox or a folder of images needs converting. Worth spreading the word to anyone who’s still paying for a PDF tool to do things Preview handles natively.