Hi Fabrice,
Thank you for using Syncfusion products.
On analyzing your code snippet, we came to know that you have directly passed Bitmap image to PdfBitmap. You have to save the bitmap into memory stream before passing it to PdfBitmap.
Please find the below code snippet,
Bitmap bitmap = somegenerationfunctionhere();
bitmap.MakeTransparent(System.Drawing.Color.White);
MemoryStream imageStream = new MemoryStream();
bitmap.Save(imageStream,System.Drawing.Imaging.ImageFormat.Png);
PdfBitmap image = new PdfBitmap(imageStream);
Please find the sample from the below link,
Please let us know if you need further assistance.
With Regards,
Gayathri R