With certain PDF documents the ExportAsImage function produces images that are missing a lot of the page content.
I have attached a zip with an example file, example MVC project, and images showing the actual output vs expected output.
You can reproduce this issue using the example code by uploading the PDF named "Input File" then clicking submit. The code will then run ExportAsImage as display the result. You can see that the result image does not have most of the text or images that were part of the document.
Attachment:
asp_pdf_3d09a858.zip