# How to Take a Screenshot on iMac

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Source: https://www.lazyscreenshots.com/blog/screenshot-imac/
Source observed: 2026-10-08T01:32:28.241Z
Last checked: 2026-10-29T01:54:31.527+00:00
Indexed: 2026-10-08T01:33:43.203+00:00

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# How to Take a Screenshot on iMac

**May 20, 2026 · LazyScreenshots Team**

We provide this guide to every standard iMac screenshot method, including Retina file sizes, multiple displays, third-party keyboards, save locations, Terminal automation, and troubleshooting. LazyScreenshots can automatically compress and beautify iMac screenshots with backgrounds, annotations, and device frames. [Try LazyScreenshots Free](https://www.lazyscreenshots.com/)

## The three keyboard shortcuts every iMac user needs

| Shortcut | What it captures |
|---|---|
| `Cmd+Shift+3` | Full screen; one file per connected display |
| `Cmd+Shift+4` | Selected area; drag a crosshair to define the region |
| `Cmd+Shift+4` then `Space` | Specific window or menu; click the highlighted window |

Each shortcut saves a PNG to the 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 unchanged.

### Copy to the clipboard

Add `Ctrl` to any shortcut to copy the capture instead of saving 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 lets you paste directly into Slack, email, or a document.

## Screenshot toolbar: `Cmd+Shift+5`

Press `Cmd+Shift+5` to open the Screenshot toolbar. It provides:

- Capture Entire Screen
- Capture Selected Window
- Capture Selected Portion
- Record Entire Screen
- Record Selected Portion

Choose **Options** to change the save location, set a 5-second or 10-second timer, show or hide the floating thumbnail, and include or exclude the mouse pointer.

## iMac display resolutions and file sizes

| iMac model | Display resolution | Full-screen screenshot size |
|---|---:|---:|
| 24-inch iMac (M1, M3, M4) | 4480 × 2520 | 5–12 MB (PNG) |
| 27-inch iMac (2019–2020) | 5120 × 2880 | 8–18 MB (PNG) |
| iMac Pro (2017) | 5120 × 2880 | 8–18 MB (PNG) |
| 21.5-inch iMac (non-Retina) | 1920 × 1080 | 1–3 MB (PNG) |

Screenshots are captured at native Retina resolution rather than the scaled resolution shown in **System Settings > Displays**. For example, a 24-inch iMac set to “Looks like 2560 × 1440” still produces a 4480 × 2520 screenshot.

To use JPG instead of PNG, run:

```bash
defaults write com.apple.screencapture type jpg
```

A 24-inch iMac JPG is typically 500 KB to 2 MB instead of 5–12 MB for PNG, with slight compression artifacts in text and UI edges.

## Multiple monitors on iMac

`Cmd+Shift+3` saves a separate PNG for each connected display. With an iMac and one external monitor, you receive two Desktop files. Timestamped filenames use a number suffix to distinguish them.

To capture only one display:

1. Press `Cmd+Shift+5`.
2. The toolbar opens on the primary display; drag it to the desired screen if needed.
3. Choose **Capture Entire Screen**, then click the specific display.

Alternatively, press `Cmd+Shift+4` and drag across the desired display or region.

With an iPad connected through Sidecar, `Cmd+Shift+3` captures the iMac and iPad as separate files. To capture only the iPad, use `Cmd+Shift+5` and click the iPad display.

## Third-party and Windows keyboards

| Mac key | Windows keyboard equivalent |
|---|---|
| `Cmd` | Windows key |
| `Option` | `Alt` |
| `Ctrl` | `Ctrl` |

The corresponding shortcuts are:

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

### Remap Print Screen

1. Open **System Settings > Keyboard > Keyboard Shortcuts > Screenshots**.
2. Select the shortcut to change, such as “Save picture of screen as a file.”
3. Press `Print Screen` to assign it.

`Print Screen` then takes a full-screen screenshot.

## Where iMac screenshots go

By default, screenshots are PNG files on the Desktop, with a name such as `Screenshot 2026-05-20 at 10.30.15 AM.png`.

### Change the location with the toolbar

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

### Set a custom folder with Terminal

For example, to use a Screenshots folder inside Pictures:

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

The folder must already exist; macOS does not create it automatically.

## iMac screenshot tips

- Hold `Option` while clicking a window in `Cmd+Shift+4` then `Space` mode to remove the window shadow.
- While dragging with `Cmd+Shift+4`, hold `Shift` to constrain movement horizontally or vertically.
- Hold `Space` while dragging to move the selection without resizing it.
- Press `Esc` to cancel a screenshot.
- Open `Cmd+Shift+5` > **Options** and uncheck **Show Floating Thumbnail** for instant saves.
- To capture a menu bar or dropdown, open the menu, press `Cmd+Shift+4`, and drag over it; the menu remains open during area selection.

## Take screenshots with Terminal

The `screencapture` command supports automation, scripts, and captures over SSH:

```bash
# 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

1. Check **System Settings > Keyboard > Keyboard Shortcuts > Screenshots** and make sure the shortcuts are enabled.
2. Check for conflicts from screenshot tools or keyboard remappers; quit third-party apps one at a time.
3. In Terminal, run `killall SystemUIServer`.
4. Check **System Settings > General > Storage** to make sure the disk is not full.
5. If using a third-party keyboard, enable **Show keyboard viewer in menu bar** under **System Settings > Keyboard** and verify that key presses register.

## Related guides

- [Mac Screenshot Keyboard Shortcuts](https://www.lazyscreenshots.com/blog/mac-screenshot-keyboard-shortcuts/)
- [How to Screenshot Multiple Monitors on Mac](https://www.lazyscreenshots.com/blog/screenshot-multiple-monitors-mac/)
- [Screenshot on Mac with External or Windows Keyboard](https://www.lazyscreenshots.com/blog/screenshot-external-keyboard-windows-mac/)
- [Where Do Screenshots Go on Mac?](https://www.lazyscreenshots.com/blog/where-do-screenshots-go-mac/)

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