I want to print as PDF, and upload (to a print-on-demand publisher) a long word document with dozens of photos in it. The images are NOT embedded or inserted, they are linked to file, so that the images have the same ppi as the original files (300ppi). I have done this several times, using dopdf and selecting the "smaller file" option (which results in a 58MB file). (The dopdf "higher quality image" option yields a 97MB file which takes a long time to upload.)
The 58MB files have always been accepted by the publisher, with all images retaining the original 300ppi. However, after making some editorial changes and re-submitting, the publisher now tells me that the images that were previously 300ppi have gone from 300ppi to as low as 170ppi. I did not change any of the images. I did add some images. My questions:
1. It is my understanding that the "smaller file" option creates a zip file, while the "higher quality image" option creates a jpeg file. Is this true?
2. Since previous files with fewer (up to 70) images have always retained their original 300ppi, and the drastic, across-the-board reduction in ppi occurred for the first time after adding a few (4) images, there seems to be a cutoff point beyond which the "smaller file" option begins to degrade the images. Is this true?
3. Any insights as to what would cause this sudden change would be most appreciated.
Misc: Running Win7, Word 2007; image ppi as per Photoshop on my end and whatever the publisher is running on their end.