This is easy. Simply address the email, including one with a picture, to this special email address:
In ten minutes or less, the email will be converted to a post. The website is instructed to check this mailbox on a ten minute cycle.
You MUST use the same email address as sender that you used to register for the site. Otherwise your post will be rejected. It is the sender’s email address that lets the website know you are legitimate.
Can you include a picture in your post via email? Of course you can.