The program only lets you post images in certain formats. .jpg or .jpeg always work. Perhaps you can convert the image to a .jpg file (Paint allows you to do this) and then upload it. To upload, you click on the "upload a file" button next to "post reply" (both are below the text box). Once you've uploaded it, below the text box you'll see a small version of the image. Next to it you'll see an option to upload a thumbnail or full image; choose full image and then hit "post reply."
Welcome, @oosheen. I hope you figure out how to upload pictures because based on your avatar of Alexandrian tetradrachms, I will want to see them
