Using an RTF document that contains images that are linked and not inserted, when saving as a PDF the images are inserted with a size of 1x1 pixels. Images that are inserted rather than linked do not have this problem.
This occurs when using either the built-in pdf save method, or the legacy save method via Aspose Pdf. Note that this problem does not occur when the images are linked inside a DOC file, rather than an RTF.
I have attached a zip file with a couple of example docs, one in RTF format and one in DOC format, along with the output pdf that is generated. I have also included the XML file that is produced when saving in legacy format, as it clearly shows the image size as being 1x1 pixels for the linked image only.