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.  
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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.  
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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.
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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.
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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.