How can I fix this problem? Acrobat duplicates my pages when I flatten images.

A file that is flattened gets SMALLER, not bigger.

I realized that if the only solution to this [RIDICULOUS!] problem was to flatten the pages in small batches and then remove the duplicate pages, I had to know which pages were the flattened ones. Is Acrobat placing the flattened pages BEFORE or AFTER the original pages? The answer: the new, flattened pages are the SECOND set of pages -- Acrobat is inserting the new, flattened pages AFTER the original pages.  Here is how I figured that out:

1. I flattened my document in groups of 10 pages, working beginning to end.

2. I checked the page count after each batch to find out when Acrobat duplicated a set of pages. Saved the file.

3. I saved a copy of the entire file as a new document [name of doc] COPY.

4. I used the Organize Pages tool to remove all of the pages EXCEPT the FIRST set of 10 duplicate pages.  I saved this as a new document: [name of doc] FRONT.

5. I went back to the COPY document and opened it again.

6. I used the Organize Pages tool to remove all of the pages EXCEPT the SECOND set of 10 duplicate pages.  I saved this as [name of doc] BACK.

7. I looked in the file directory to see which test document -- FRONT or BACK -- was smaller. It was the SECOND test document.

8. I went back to the original document that contained duplicated pages and deleted the FRONT set of 10 pages, leaving the smaller, presumably flattened BACK set of pages in the document.

I hope to h!@#)(*&% that the pages are ACTUALLY flattened, because I can't upload the book to KDP for printing until I have a truly flattened document. Wish me luck!

I still haven't found a fix for this. One thing that I found to work sometimes was to just flatten the pages that are giving you trouble separately, individually, but even then it sometimes duplicated some of the pages. After trying to fix it for way more time than it was worth, I ended up just sending it to the printer with a note about it.
Hoping we see some solutions for this soon. Good Luck!

Ah wait, is the problem that the file is bigger, or that some pages are duplicated?

Some of the terms by various artists are phrased as follows:

Securing and locking down images is required for all products.

Clipart should be merged into your product so your customers are not able to extract and reuse the clipart.

File must be personalized for your customer and sold as a flattened JPEG or PDF files.

They (clipart) must be sold in a flattened format such as a locked PDF in order to prevent the graphics from being lifted.

And here's a link to one site:

Terms of Use

Some of the graphic designers I purchase clipart from require that the images be flattened.