With GemBox.Pdf we can import PNG, JPG, BMP, TIFF, etc. images, but we can't import SVG images.
This feature request is for adding support for loading SVG images.
Currently, the only workaround to achieve this is by combining both GemBox.Pdf and GemBox.Document. In that case with GemBox.Document we create a PDF file that contains an SVG image and with GemBox.Pdf we append the content of that PDF page into some other existing PDF page.