Document Upload Issues

Our IT department has brought up an issue that is occuring when our vendors are trying to convert documents to upload into Vendor Plus. It seems to be happening mainly with our Loss Draft product but you are not allowed to change the file type on a PDF file just so you can upload that into Vendor Plus. In other words, if the file is in a PDF format, you can't just change the extension to JPG and load the file. You haven't converted the actual document, you have just changed the extension. Vendor Plus will let you upload because it is reading the extension but we can't view that particular upload or other photos that were submitted at the same time. This is causing delays to us and our clients so please refrain from changing the extension on those documents without converting the entire document to the proper file type. Thanks