Thank you for contacting Syncfusion support.
We have analyzed your requirement, but we could not able to set the resolution for PDF document. However we can able to set the resolution for image which has been exported from PDF document. Please refer the below code snippet for more details,
//Load the existing PDF document
PdfLoadedDocument loadedDocument = new PdfLoadedDocument("HTTP Succinctly.pdf");
//Get the PDF page count
int count = loadedDocument.Pages.Count;
//Convert each page to image file
for (int i = 0; i < count; i++)
//Export PDF page to image
Image image = loadedDocument.ExportAsImage(i, 300, 300);
//Save the exported image
image.Save("Image" + i + ".png", System.Drawing.Imaging.ImageFormat.Png);
We can also set the zoom level to view page of PDF document. Please refer the below UG documentation link for more details,
Please let us know if you need any further assistance on this.