Smaller in which way exactly and according to which application’s display?
Could you please post screenshots to illustrate the issue?
Are you using a retina display?
What were the pdf settings you used?
High Quality Print
Do Not Downsample
Sounds like the OS is just seeing the thumbnail, and Bridge is getting the thumbnail from the OS as well.
If you open the pdf with Photoshop (Images, not Pages!) what are the pixel dimensions?
I saved the 1024x748px jpg as a pdf with Photoshop.
Bridge says its now a 246x180 pdf.
Apple Finder says it’s a 245x179 pdf.
Apple Preview shows it to be small.
When I reopen it in Photoshop, Photoshop says it’s 1024x748 (and looks like it).
I like your suggestion that it’s a thumbnail related problem and I wonder if I should be looking at Apple support sites. Your help is appreciated.