Not one system I know of maintains page margins (in Windows.)
Why this is, might take weeks to convey to someone that hasn't been under the hood of Windows but suffice it to say that for now, such control is back in the host's control. That is, when I print I set such print margins and if I take a BMP and stick it into a PDF I can with a lot of cajoling get identical output.
For me, it's not worth the effort but in your case you may have to exert such control.
Bitmap printout and pdf conversion in MGI Photosuite shifts margins from saved file size to a larger margin. Used other converters (CutePDF, Apex Creator...etc) with same result. Is there a s/w that maintains paper size to original image page size without defaulting to (Adobe margin expansion) vector properties?