See these posts and then come back with additional, specific Qs if you have them:
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http://www.theeroticreview.com/discussion-boards/newbie---faq-33/posting-pics-170651
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http://www.theeroticreview.com/discussion-boards/newbie---faq-33/how-to-post-pics-recap-170843
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http://www.theeroticreview.com/discussion-boards/newbie---faq-33/minimally-youll-need-a-photo-hosting-site-171130
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http://www.theeroticreview.com/discussion-boards/newbie---faq-33/1-image-host-site-2-link-on-ter--167867

And others ...

To help further with directions, I found a website about compasses and I copied the this URL:
https://s3.amazonaws.com/cdn.teachersource.com/images/popup/mag150.jpg
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I pasted that URL into the "Picture URL" box at the bottom of the posting page.
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Then I hit "Post Message."  
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TER does not store photos attached to posts. When you open this post in your browser, TER "knows" to tell that website to download the image to YOUR browser so you can see the pic.