Windows allows you to convert any image file with JPG, JPEG, PNG format to PDF without installing any third-party software via Windows Photos App.

Pick Save as PDF to choose a filename and destination, and you can even add password protection to the document if you want to. There's PDF functionality built right into Finder as well.

To convert a JPG file to a PDF file, simply change the file format on your computer's default photo-viewing app.

In the Preview app, for example, it's possible to create a single multi-page PDF document out of several separate image files.