I think that option says “Print All Images”. if you have multiple images within an attachment field, it will try to squeeze all of the images into the predetermined box size that you have created on the layout.
However, one of the biggest flaws & major problems with Page Designer is that it will NEVER create an additional page for ANYTHING when printing a record — whether it’s multiple linked records, multiple images, multiple pages of a PDF file, anything. Page Designer will only allow for one page per record, and that’s it.
So if you have a multi-page PDF file that you’re trying to print with Page Designer, you are also out of luck. It will only ever show the first page of a PDF file in Page Designer.
I would recommend sending an email to firstname.lastname@example.org to ask them to please improve the capabilities of Page Designer to support multiple pages.