We have tried the sample to insert image into PDF with the provided image file. We were able to view the wrong image dimension. This behavior occurs because, some Bitmap objects does not take into account the EXIF Orientation tag. The EXIF (Exchangeable Image File Format) standard specifies some set of tags that can be embedded in images. One of these tags specifies the orientation of the image. If it does take into the account, the image get rotated. This behavior will be reproduced even in System.Diagram.Bitmap. However, we have created the sample to draw the image properly to PDF page without any rotation. Please find the sample for the same from below location,
Please try this workaround sample in your end and let us know whether it solves the issue.