Booklet preview showing small thumbnails

Hello,

You're encountering a common issue when creating booklets in Adobe Acrobat, especially when combining PDFs from different sources or with varying page sizes. Here's a breakdown of the problem and how to fix it:

Understanding the Problem

Page Size Mismatch:
Your original Photoshop images likely have a specific resolution and pixel dimensions, which translate to a certain page size when converted to PDF.
Acrobat's booklet printing function tries to fit these pages onto the target tabloid/ledger sheet according to the chosen settings. If the original pages are smaller than the target, they will appear small.
Scaling Issues:
Acrobat's booklet printing options have scaling settings that might not be correctly configured.
There might also be scaling settings embedded in the individual PDF files you've created from Photoshop.
PDF Creation Settings:
It is possible that when you created the pdfs from photoshop, that you did not set the correct page size.
Troubleshooting Steps

Verify Original PDF Page Sizes:

Open each of your Photoshop-generated PDFs in Acrobat.
Go to "File" > "Properties."    
Check the "Page Size" in the "Description" tab.
Ensure that the page size of the pdfs you created match the size that you want them to be in the final booklet.
If the page sizes are not correct, you will need to re-export the pdfs from photoshop with the correct page dimensions.

Best Regards