STEPS
TOOLS
Select all the photos you want to put in your pdf file. Right click open in preview (Mac default program)
Select every photos on your side bar.
File > print
At the bottom left corner click pdf and choose save as pdf
Change the name to whatever name you want .pdf
Click save
Done!
You combine all the pictures into one file successfully. Cheers!
 Photos
 Mac OS
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How to create a pdf file from jpg photos on mac os

Creating multi page single pdf file from your many photos or scanned document.