how do you post pictures

These 2 posts should get you going..

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If you are responding to a thread, you must click on the "post reply" at the top of the thread and not the "post quick reply" on the bottom. Once you add your comments, then you go to the bottom of that page and click "manage attachments" and follow the directions to add attachment/picture.
You do the same thing regarding managing attachments when starting a new thread.