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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If you were a computer guru, you could set up your personal computer to be "server" that could serve (deliver) the pictures but that is too complicated and insecure.  
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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 Taylor, I found a picture of a tailor here, on shutterstock:
https://thumb7.shutterstock.com/display_pic_with_logo/704791/336177197/stock-vector-tailor-doodle-cartoon-design-illustration-336177197.jpg
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(In the body of a post, the s in httpS keeps it from being a "hot link.") 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.
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TER is just the middle man, telling shutterstock to send that pic file to your computer to display in your browser.