Mac 笔记本电脑和台式机将屏幕截图保存为 PNG 图像文件(save screenshots as PNG image files)。本指南将介绍将这些屏幕截图转换为PDF和JPG格式的不同方法。您还将了解如何更改默认文件格式以在Mac上保存屏幕截图。
在我们继续之前，下一部分是快速复习，重点介绍在 macOS 设备上截取屏幕截图的不同方法。
如何在 Mac 上截屏
Mac(Macs)有多个键盘快捷键，用于捕获不同类型的屏幕截图。触控栏(Bar)（适用于MacBook Pro(MacBook Pros)）也有一个专用的“屏幕截图”工具用于相同目的。
方法 1：使用键盘快捷键(Method 1: Using Keyboard Shortcuts)
同时按下Shift + Command + 3将截取整个屏幕。
要捕获屏幕的一部分，请按Shift + Command + 4并使用十字准线工具选择要捕获的区域。要移动所选区域，请按空格键(Spacebar)（不要从触控板上抬起手指）并将所选区域拖动到首选区域。
如果您的MacBook有触控栏(Touch Bar)，请按Shift + Command + 6捕获触控栏屏幕。
方法 2：从触控栏控制条(Method 2: From the Touch Bar Control Strip)
您还可以使用触控栏截取(Touch Bar)MacBook屏幕的屏幕截图。展开控制条(Control Strip)并点击屏幕截图(Screenshot)图标。
在捕获的选定部分(Captured Selected Portion)部分中，选择要捕获的区域，然后在屏幕截图菜单上选择捕获。(Capture)
要使用触控栏(Touch Bar)捕获整个Mac显示屏，请选择最左侧的捕获整个屏幕图标，然后选择(Capture Entire Screen)捕获(Capture)。
还有一个捕获应用程序窗口的选项。选择Capture Selected Window图标，将(Capture Selected Window)相机图标(camera icon)悬停在要截屏的应用程序上，然后选择应用程序窗口上的任意位置。
在 Mac 上编辑屏幕截图
无论您采用哪种方法，您的Mac都会在屏幕的右下角显示屏幕截图的缩略图。
点击缩略图将启动一个预览(Preview)窗口，您可以在其中调整屏幕截图的大小和裁剪、添加文本和形状、插入签名，或通过AirDrop、Messages、Mail等共享屏幕截图。
此内置编辑器还允许您将屏幕截图转换为其他文件格式。
在 Mac 上转换屏幕截图
我们假设您已经知道有不同的图像格式。默认情况下，macOS 以便携式网络图形(Portable Network Graphic)( PNG ) 格式保存屏幕截图。以这种格式保存的图像比JPG、BMP(common formats like JPG, BMP)等其他常见格式具有更高的质量和更大的文件大小。
将屏幕截图转换为JPEG格式有助于节省 Mac 的存储空间。您可能还需要将屏幕截图转换为可移植文档格式(Document Format)( PDF ) 以满足某些平台或网站的文件上传要求。
幸运的是，内置的 macOS 编辑器可让您将屏幕截图从默认的PNG格式转换为JPEG（或JPG）、TIFF、HEIC、PDF 等。
1. 在 Mac 上将屏幕截图转换为 PDF
使用键盘快捷键或触控栏(Bar)捕获屏幕区域，然后按照以下步骤将屏幕截图转换为PDF文件。
- 双击或双击屏幕截图以使用预览(Preview)——macOS 内置图像和PDF编辑器打开它。
或者，按住 Control 键单击屏幕截图，选择Open With并选择Preview。
- 选择菜单栏上的文件，然后选择导出(File)为 PDF(Export to PDF)。
- 在“另存(Save)为”对话框中重命名文件，点击“位置”下拉选项以选择要保存文件的位置，然后选择“保存(Save)” 。
2. 在 Mac 上将屏幕截图转换为 JPG
在Mac上将屏幕截图重新散列为JPG遵循相同的过程。只是 macOS JPG转换工具稍微高级一点——您可以选择生成的JPG文件的图像质量。
- 按住 Control 键单击(Control-click)屏幕截图，在上下文菜单中选择打开方式，然后选择(Open With)预览(Preview)。
- 选择菜单栏上的文件，然后选择(File)导出(Export)。
- 在“导出为”对话框中为屏幕截图指定一个新名称/标题，然后在“位置”对话框中选择您希望文件保存的首选位置。将“质量(Quality)”滑块移动到最右侧，将屏幕截图转换为“最佳(Best)” JPEG质量。
3.使用在线文件转换器将屏幕截图转换(Convert Screenshot)为PDF或JPG(JPG Using Online File)
有几种基于在线的文件转换工具可以将您的Mac屏幕截图转换为JPG图像和PDF文档。Online-Convert 和ZamZam是信誉良好的在线工具的好例子，可让您在不同文件类型之间进行转换(online tools that let you convert between different files types)。
在您的网络浏览器上访问(Visit)这些平台，上传屏幕截图，选择您想要将屏幕截图转换为的图像或文档格式，然后将生成的文件下载到您的Mac上。
4.在Mac上更改屏幕截图的(Screenshots)默认文件格式(Default File Format)
如前所述，macOS 默认将屏幕截图保存为PNG文件格式。经常将 ( PNG ) 屏幕截图转换为其他文件格式可能会带来压力。永久配置您的Mac以将屏幕截图保存为您常用的文件格式，这将为您节省大量时间、精力和存储空间。
如果您的 Mac 存储空间不足，我们特别建议将屏幕截图的默认格式更改为JPG 。这是因为PNG文件通常比(PNG)JPG和PDF文件消耗更多的存储空间。
下图突出显示了我们在测试 MacBook 上同时拍摄的三个屏幕截图（不同格式）的文件大小。
PNG屏幕截图占用的存储空间最多（3.1 MB），其次是PDF（2.7 MB）和JPG（680 KB）屏幕截图。
- 转到Finder > Applications > Utilities并双击Terminal。
- 在终端控制台中键入或粘贴默认值，写入 com.apple.screencapture type JPG(defaults write com.apple.screencapture type JPG)并按Enter。
此命令指示您的Mac以JPG格式保存屏幕截图文件。
- 要将屏幕截图保存为PDF文件，请在终端控制台中粘贴默认值写入 com.apple.screencapture 类型 PDF(defaults write com.apple.screencapture type PDF)并按Enter。
展望未来，您的Mac将以PDF文件格式保存屏幕截图。macOS 还允许您将屏幕截图保存为其他多媒体格式，例如TIFF和GIF。您需要做的就是在终端窗口中粘贴默认(All)写入com.apple.screencapture 类型 TIFF(defaults write com.apple.screencapture type TIFF)或默认写入 com.apple.screencapture 类型 GIF ，然后按(defaults write com.apple.screencapture type GIF)Enter。
这些命令会将 Mac 屏幕截图的默认文件格式分别更改为TIFF或GIF。
要将默认屏幕截图文件格式更改为PNG ，请在终端窗口中粘贴默认设置，写入 com.apple.screencapture 类型 PNG ，然后按(defaults write com.apple.screencapture type PNG)Enter。
要确认您的 Mac 的屏幕截图格式是否已更改，请截取屏幕截图并检查文件详细信息。
右键单击或按住 Control 键单击屏幕截图，在上下文菜单中选择Get Info ，然后检查(Get Info)General部分中的“Kind”行。
如果截图格式没有变化，重新运行相应的命令，再截一张，再次检查图像格式。如果您仍然无法更改屏幕截图文件格式，请重新启动Mac 并重(Mac)试。
如果您在捕获、编辑或转换屏幕截图时遇到 问题，请参阅此故障排除指南以解决 Mac 上与屏幕截图相关的问题。(troubleshooting guide on fixing screenshot-related issues on Mac)
4 Ways to Convert Screenshot to PDF and JPG on Mac
Mаc notebooks and desktops save screenshots as PNG image files. This guide will cover different ways to convert these screenshots to PDF and JPG formats. You’ll also learn how to change the default file formats for saving screenshots on your Mac.
Before we proceed, the next section is a quick refresher highlighting the different ways to take screenshots on macOS devices.
How to Take Screenshot on Mac
Macs have multiple keyboard shortcuts for capturing different types of screenshots. The Touch Bar (for MacBook Pros) also has a dedicated “Screenshot” tool for the same purpose.
Method 1: Using Keyboard Shortcuts
Pressing Shift + Command + 3 simultaneously will take a screenshot of the entire screen.
To capture a portion of the screen, press Shift + Command + 4 and use the crosshair tool to select the area you want to capture. To move the selected area, press the Spacebar (without raising your finger from the trackpad) and drag the selection to the preferred area.
If your MacBook has a Touch Bar, press Shift + Command + 6 to capture the Touch Bar screen.
Method 2: From the Touch Bar Control Strip
You can also take a screenshot of your MacBook screen using the Touch Bar. Expand the Control Strip and tap the Screenshot icon.
In the Captured Selected Portion section, select the area you want to capture, and select Capture on the screenshot menu.
To capture the entire Mac display using the Touch Bar, select the Capture Entire Screen icon on the far-left, and select Capture.
There’s an option to capture an app window, too. Select the Capture Selected Window icon, hover the camera icon on the app you want to screenshot, and select anywhere on the app window.
Editing Screenshots on Mac
Whatever method you adopt, your Mac will display a thumbnail of the screenshot in the bottom-right corner of the screen.
Tapping the thumbnail will launch a Preview window where you can resize and crop the screenshot, add texts and shapes, insert signatures, or share the screenshot via AirDrop, Messages, Mail, etc.
This built-in editor also lets you convert screenshots to other file formats.
Converting Screenshot on Mac
We assume you already know that there are different image formats. macOS, by default, saves screenshots in Portable Network Graphic (PNG) format. Images saved in this format have superior quality and larger file size over other common formats like JPG, BMP, etc.
Converting screenshots to JPEG format can help save your Mac’s storage space. You might also need to convert screenshots to Portable Document Format (PDF) to meet the file upload requirements of certain platforms or websites.
Luckily, the built-in macOS editor lets you convert screenshots from the default PNG format to JPEG (or JPG), TIFF, HEIC, PDF, etc.
1. Convert Screenshot to PDF on Mac
Capture the area of the screen using keyboard shortcuts or the Touch Bar and follow the steps below to convert the screenshot to a PDF file.
- Double-click or double-tap the screenshot to open it with Preview—macOS built-in image and PDF editor.
Alternatively, control-click the screenshot, select Open With and select Preview.
- Select File on the menu bar and select Export to PDF.
- Rename the file in the “Save as” dialog, tap the “Where” drop-down option to select where you want the file saved, and select Save.
2. Convert Screenshot to JPG on Mac
Rehashing screenshots to JPG on Mac follows the same process. Only that the macOS JPG conversion tool is a little more advanced—you get to choose the image quality of the resulting JPG file.
- Control-click the screenshot, select Open With on the context menu, and select Preview.
- Select File on the menu bar and select Export.
- Give the screenshot a new name/title in the “Export As” dialog box and select the preferred location you want the file saved in the “Where” dialog box. Move the Quality slider to the far right to convert the screenshot to the “Best” JPEG quality.
3. Convert Screenshot to PDF or JPG Using Online File Converters
There are several online-based file conversion tools that can convert your Mac screenshots to JPG images and PDF documents. Online-Convert and ZamZam are good examples of reputable online tools that let you convert between different files types.
Visit these platforms on your web browser, upload the screenshot, select the image or document format you want the screenshot converted to, and download the resulting file to your Mac.
4. Change Default File Format For Screenshots on Mac
As mentioned earlier, macOS saves screenshots in PNG file formats by default. Frequently converting (PNG) screenshots to other file formats can be stressful. Permanently configuring your Mac to save screenshots in your frequently-used file format will save you a lot of time, energy, and storage space.
We particularly recommend changing the default format for screenshots to JPG if your Mac’s storage is running low. That’s because PNG files often consume more storage space than JPG and PDF documents.
The image below highlights the file sizes of three screenshots (in different formats) we took at the same time on our test MacBook.
The PNG screenshot consumed the most storage space (3.1 MB) followed by the PDF (2.7 MB) and JPG (680 KB) screenshots.
- Go to Finder > Applications > Utilities and double-click Terminal.
- Type or paste defaults write com.apple.screencapture type JPG in the Terminal console and press Enter.
This command instructs your Mac to save screenshots files in JPG format.
- To save screenshots as PDF files, paste defaults write com.apple.screencapture type PDF in the Terminal console and press Enter.
Moving forward, your Mac will save screenshots in PDF file format. macOS also lets you save screen captures to other multimedia formats like TIFF and GIF. All you need to do is paste defaults write com.apple.screencapture type TIFF or defaults write com.apple.screencapture type GIF in the Terminal window and press Enter.
These commands will change the default file format for your Mac’s screenshots to TIFF or GIF, respectively.
To change the default screenshot file format to PNG, paste defaults write com.apple.screencapture type PNG in the Terminal window and press Enter.
To confirm if your Mac’s screenshot format has changed, take a screenshot and check the file details.
Right-click or control-click a screenshot, select Get Info on the context menu and check the “Kind” row in the General section.
If the screenshot format remains unchanged, re-run the appropriate command, take another screenshot, and check the image format again. If you’re still unable to change the screenshot file format, restart your Mac and try again.
Refer to this troubleshooting guide on fixing screenshot-related issues on Mac if you’re having troubles with capturing, editing, or converting screenshots.
