How to compress a PDF for emailing or sharing?
如何压缩 PDF 以发送电子邮件或分享？
There are plenty of online and offline tools that allow you to compress PDFs and make them easier to share in different ways. However, most of these free online compressors do not allow any level of compression customization, which means you don't have any control over the extent the file is reduced to. Keep in mind that security is important when working with online tools. With offline PDF compressors, such as PDF Extra, you work locally on your desktop where security is not an issue. With PDF Extra's compression you can also decide how much the embedded images' file size will be reduced.
有很多在线和离线工具，可压缩 PDF，使其更便于以各种不同方式分享。 但是，这些免费的在线压缩器大多数都不允许自定义压缩级别，这意味着您无法控制文件压缩程度。 请记住，使用在线工具时，安全性非常重要。 使用离线 PDF 压缩器（例如 PDF Extra），您可在桌面上本地工作，安全性不是问题。 使用 PDF Extra 的压缩功能，您还可以决定嵌入图像的文件压缩程度。