Prevent downsampling of 32-bit images from Microsoft Word?

After conversion to PDF, any 32-bit images (i.e. with an alpha channel, either PNG or TIFF) in a Microsoft Word document are resampled to a much lower resolution (800 -> 300 dpi).  All other images (24-bit) maintain their original resolution.

I encounter this problem when using both lossless (ZIP) image compression and no image compression in PDFCreator.

Does anyone know if this problem can be avoided without converting my images from 32-bit to 24-bit?  Or is this an unavoidable problem of Word?

A different but potentially related problem can be seen by converting the Word document on the following page.  The image does not have a high enough resolution to trigger the resampling, but the image is clearly modified by the conversion (affecting transparency).

PDFCreator 2.3.0 (build 103)
Microsoft Word 2016 (16.0.6001.1061) 32-bit

I have PDFCreator set to High Quality with image resampling disabled.
I have a Microsoft Word document with 800 dpi images that are stored without compression (Options -> Advanced -> Do not compress images in file).


all transperancy will get lost during the conversion to Postscript, but I am not sure why this would cause the resampling to a lower resolution. What DPI is the virtual PDFCreator printer set to (in the advanced properties of the printer in the Windows control panel)?

best regards,