Go to http://png2pdf.com/ in your computer's web browser. If you weren't able to scan a document directly into a PDF, this website will allow you to turn a scanned image (e.g., a PNG) file into a PDF. If you scanned your document into your computer as a JPG file, go to http://jpg2pdf.com/ instead. It's in the middle of the page. Doing so opens a File Explorer (Windows) or Finder (Mac) window. Go to the folder in which your scanned image was saved, then click the image to select it. It's in the bottom-right corner of the window. This will upload the image to the PNG (or JPG) to PDF site. This should only take a few seconds. It's below your converted file in the middle of the window. Doing so will prompt your PDF to download onto your computer.

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Write a summary of the previous text in Chinese:
打开PNG to PDF网站。 点击上传文件。 选择扫描的图片。 点击打开。 等待图片转换成PDF。 点击下载。