PDF SEO's PDF file compression (with PDF online compression website)

PDF文档优化（PDF SEO) PDF file compression.

If a PDF file does not pay attention to the size of compression, upload such PDF to the website, due to the restriction of network bandwidth, users can not download it locally for browsing.

如下图所示，一个165MB的PDF，压缩之后，只有1MB，明显方便了用户在线浏览与下载。


附上三个PDF文档在线压缩网站：

https://smallpdf.com/cn/compress-pdf

http://www.ilovepdf.com/zh_en/compress_pdf 

https://foxyutils.com/compresspdf/