Open-source might not be the first thing you think of with Windows, but these free tools can seriously boost your productivity.

Learn how to count pages in multiple PDF files together in Windows 11/10 using a web browser and free PDF page counter tools.

If you keep Chrome up-to-date without changing any settings, any PDF you download may open within the web browser by default.

I am not sure why but people treat PDF differently than image files so I don't think there are very many that work for quickly viewing PDF *and* image files but you can certainly use something ...