Nice meeting you. I don't know much about Facebook (OK, I don't know anything about FB), but here are the basics for posting pics here:
-Upload picture somewhere
-Find & copy picture URL
-Paste URL into a message here
-Click Preview - if you like it, click Respond! or Post!
That's about it. Image has to be jpg or gif format. Link can not be secure (must start with http, not https) to automatically display.
Here's some tips I wrote for posting images if you want to resize / hyperlink: