Question: Can I upload an image or a pdf file?
Yes.
How: Use the “attachment” link (just above the SUBMIT button below). The size is limited, however, so if you get a file is too large message, use the “Contact Us” tab to ask if you can upload it. Give the particulars of your file (type and size) and the reason you need to upload it.
When you open an uploaded attachment, it will open in a new browser tab. Important: Use the back arrow to exit from it and return to where you were before opening it. If you close the tab, it will throw you out of the forum … hmmmm … this WordPress plugin feature needs improving!