The answer to the second part of the question is...you can't, but you can use the @ sign and their name to draw attention to your post and you can use the Quote feature to repost it.
I just had to try the 1st part, I used the "Upload and Image" button for the image, then just typed in description on the same line starting at the end of the brackets. If that is what you were asking.
'Sparks One Hot Mama'
'Sparks One Hot Mama'
