This belongs in Q&A. MOVED.

But to answer your question. . .

You have to go to 'new reply' and near the bottom of that screen there will be a box that 'Attach File', click browse or whatever. Then find the pic you want and attch the file and post the reply.

If you meant "How do I put a picture in my sig?", you have to the code. . . Which I dom't know of the top of my head.