When you open 'Additional Options, you will see 3 boxes you can tick, then below that is the space for attaching a photo. Click on the 'Browse' thingy, you can then select the image on your PC.
Once you have found it, click "Open" which is at the bottom right hand side of the box that opens up, and it automatically puts the location of the image in the space provided. When you click 'Post' it automatically comes up.
I've probably confused you more, but just try it and hopefully it will become more clear than what I've described............
See.................
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