...imagecoast.com. There are others. You load your photos to that site. They will then have a url. Copy/paste the url into the box at the bottom of the posting window on TER. (It's labled photo or picture url.) Then when you click the post message button your photo will show in your post when you open it. Remember no contact information is allowed in photo posts on the Photo Only Board.

TER does not "host" image files. They take up too much storage space. So, you can only post a LINK to the image that is stored on someone else's computers.  
.
That computer must be set up to allow "public" access / viewing.  When I open your post on TER, the browser and TER's computers detect that there is a link to an image file. TER sends a message to that host site to send the picture with that URL (address) to my browser. I get the frames, the text, the TER logos from TER but the picture comes from imagecoast.com or some other non-TER computer.  
.
Create an account on a dedicated picture hosting site, e.g., imagecoast. Upload pics from your computer (or phone) to that account. Use the URL from the hosting site in your TER ads and posts.
.
Here's an example. Because you are a Benjamin, I found a picture of a Benjamin here, on alamy.com. The URL is:  http://c8.alamy.com/comp/DTH3JX/us-100-dollar-bill-DTH3JX.jpg  That picture file is not on my computer; it is not on the TER computers; it is stored alamy.com's computers.
.
I am pasting that same link into the Picture URL [    ] box at the bottom of the posting page and the pic will appear in the post you actually see.