Same as the OP.
I do not have a printer installed on my laptop, but I want to export prints to JPG files to send to a commercial printer.
So how do I define unusual paper sizes? (I only see Office paper sizes!)
I think I have answered my own question-
Set Print Job to "Print to: JPG File", Define paper size in "Custom File Dimensions"..
So you were able to change the size? Where under page set up? I have a printer installed and on my drop down I have user defined. But don't know where I can manually change the size to 16x20
Apparently You do not need 'Page Setup' if you select the [ Print to: JPEG File ] in the Print Job Panel.
Further down in the same panel you can tick the [Custom File Dimensions: ] and enter your proposed size print.
Then go back up the panels and reset margins for cell sizes, and layout, etc.
You will also need to save the new print design as a template/Preset.
When you Print to File you give the new JPG file a name and save-
Thank You so much !! That worked. I tested the result on Costco Print Center site with no cropping issues. One last thing what resolution ppi are you saving your collages?
You will find a full complete answer to your question- "resolution ppi" from Laura Shoe at-