How to Take a Screenshot on iMac

Why iMac screenshots are different from MacBook screenshots

The screenshot shortcuts on iMac are identical to every other Mac. But iMac users face situations that laptop owners don’t: large Retina displays that produce enormous screenshot files, dual-monitor setups with an external display alongside the built-in screen, and third-party keyboards that don’t have a Cmd key. This guide covers the standard shortcuts first, then digs into the iMac-specific details that most guides skip.

The three keyboard shortcuts every iMac user needs

Every shortcut saves a PNG file to your Desktop by default. A floating thumbnail appears in the bottom-right corner for five seconds — click it to annotate with Markup, or let it disappear to save the file as-is.

Copy to clipboard instead of saving a file

Add Ctrl to any shortcut above to copy the screenshot to your clipboard instead of saving it as a file:

• Ctrl+Cmd+Shift+3 — full screen to clipboard
• Ctrl+Cmd+Shift+4 — selected area to clipboard
• Ctrl+Cmd+Shift+4 then Space — window to clipboard

This is useful when you want to paste a screenshot directly into Slack, an email, or a document without creating a file on your Desktop.

Using the Screenshot toolbar (Cmd+Shift+5)

Press Cmd+Shift+5 to open the Screenshot toolbar at the bottom of your screen. This gives you a visual interface with buttons for:

• Capture Entire Screen
• Capture Selected Window
• Capture Selected Portion
• Record Entire Screen
• Record Selected Portion

Click Options in the toolbar to change the save location, set a 5-second or 10-second timer, choose whether to show the floating thumbnail, and toggle the mouse pointer in captures.

iMac display resolutions and screenshot file sizes

iMac screens are large and high-resolution, which means screenshots are significantly bigger files than what you’d get from a MacBook Air or MacBook Pro. Here’s what to expect:

Screenshots are always captured at native Retina resolution, not the scaled resolution you see in System Settings > Displays. So even if your 24-inch iMac is set to “Looks like 2560 × 1440,” the screenshot is 4480 × 2520 pixels.

If file size is a concern — for example, when attaching screenshots to email or uploading to Jira — consider switching the default format from PNG to JPG. Run this in Terminal:

defaults write com.apple.screencapture type jpg

JPG screenshots from a 24-inch iMac are typically 500 KB to 2 MB instead of 5–12 MB for PNG, at the cost of slight compression artifacts in text and UI edges.

Screenshots with multiple monitors on iMac

Many iMac owners connect a second display — an external monitor, a Studio Display, or even an iPad via Sidecar. Screenshot behavior changes with multiple screens:

Cmd+Shift+3 captures all displays

Pressing Cmd+Shift+3 saves a separate PNG file for each connected display. If you have the iMac screen plus one external monitor, you get two files on your Desktop. The files are named with a timestamp and a number suffix to distinguish them.

Capture only one screen

To screenshot just one display without the others:

1. Press Cmd+Shift+5 to open the Screenshot toolbar
2. The toolbar appears on your primary display — drag it to the screen you want to capture if needed
3. Click Capture Entire Screen, then click on the specific screen you want

Alternatively, use Cmd+Shift+4 and drag a selection across just the screen you want. This works when you need a specific region on one display.

Sidecar (iPad as second display)

If you’re using an iPad as a second display via Sidecar, Cmd+Shift+3 captures both the iMac screen and the iPad screen as separate files. To capture only the iPad screen, use Cmd+Shift+5 and click on the iPad display.

Taking screenshots with a third-party or Windows keyboard on iMac

Unlike MacBooks with built-in keyboards, every iMac uses an external keyboard — and not everyone uses the Apple Magic Keyboard. If you’re using a Windows keyboard, mechanical keyboard, or other third-party board, here’s how the keys map:

So the screenshot shortcuts become:

• Win+Shift+3 — full screen
• Win+Shift+4 — selected area
• Win+Shift+5 — Screenshot toolbar

Remapping the Print Screen key

If your keyboard has a Print Screen key and you want it to take a screenshot like it does on Windows:

1. Open System Settings > Keyboard > Keyboard Shortcuts > Screenshots
2. Click the shortcut you want to change (e.g., “Save picture of screen as a file”)
3. Press Print Screen on your keyboard to assign it

Now pressing Print Screen takes a full-screen screenshot, just like on Windows.

Where do iMac screenshots go?

By default, every screenshot saves to your Desktop as a PNG file named something like Screenshot 2026-05-20 at 10.30.15 AM.png. To change the save location:

Using the Screenshot toolbar

1. Press Cmd+Shift+5
2. Click Options
3. Under Save to, choose Desktop, Documents, Clipboard, Mail, Messages, Preview, or Other Location

Using Terminal

To set a custom folder (for example, a Screenshots folder inside Pictures):

defaults write com.apple.screencapture location ~/Pictures/Screenshots
killall SystemUIServer

All future screenshots will save to that folder. The folder must already exist — macOS won’t create it for you.

iMac screenshot tips and tricks

• Remove the window shadow — hold Option while clicking a window in Cmd+Shift+4+Space mode to capture without the drop shadow
• Lock the selection to a dimension — while dragging with Cmd+Shift+4, hold Shift to lock the selection to horizontal or vertical movement only
• Move the selection while drawing — hold Space while dragging to reposition the selection area without resizing it
• Cancel a screenshot — press Esc at any point to cancel
• Disable the floating thumbnail — open Cmd+Shift+5, click Options, and uncheck Show Floating Thumbnail for instant saves
• Screenshot the menu bar or a dropdown — open the menu, then press Cmd+Shift+4 and drag over the menu. The menu stays open during area selection

Taking screenshots on iMac with Terminal

The screencapture command gives you programmatic control over screenshots. This is useful for automation, scripts, or capturing from SSH:

# Full screen to file
screencapture ~/Desktop/screenshot.png

# Interactive selection (same as Cmd+Shift+4)
screencapture -i ~/Desktop/screenshot.png

# Specific window (same as Cmd+Shift+4+Space)
screencapture -iW ~/Desktop/screenshot.png

# Capture to clipboard
screencapture -c

# Timed capture (5-second delay)
screencapture -T 5 ~/Desktop/screenshot.png

# Capture without the window shadow
screencapture -iWo ~/Desktop/screenshot.png

Screenshot not working on iMac? Quick fixes

If screenshot shortcuts aren’t responding on your iMac:

1. Check keyboard shortcuts are enabled — go to System Settings > Keyboard > Keyboard Shortcuts > Screenshots and make sure all shortcuts are checked
2. Check for app conflicts — some apps (like certain screenshot tools or keyboard remappers) override the default shortcuts. Quit third-party apps one at a time to find the conflict
3. Restart SystemUIServer — open Terminal and run killall SystemUIServer
4. Check disk space — screenshots won’t save if your iMac’s storage is full. Check System Settings > General > Storage
5. Test with the built-in keyboard viewer — if you’re using a third-party keyboard, open System Settings > Keyboard and enable Show keyboard viewer in menu bar to verify your key presses are registering correctly