We have used the default image and PDF viewer on Mac, the Preview, to convert them from one format to another in previous articles. For example, you can see how to combine and convert multiple photos to PDF using Preview on Mac. The easiest way to convert multiple images to PDF or create PDF files from images however should the the Create PDF quick action tool in Finder.
Put all the images you like to convert into PDF into one folder in Finder. Select all of them, right click or press the Control key and click to get the context menu, choose Quick Actions > Create PDF.
Wow! Look at that, the new PDF file just created in the same folder as those images in no time. Double click to open the PDF file in Preview, you will find all images are converted to pages in the PDF file.