include photo:
[photoid=xxxxxx]
where xxxxxx is the number of the photo
reply: each post has a Quote button. to the right of that button is an "+ button. Click on that for each post you want to quote - you will see the button turn red. For the last post you want to quote, click on Quote and you will find the entire contents of each of the posts in your draft message. You can then cut down each quote to include only the material you want. Remember not to delete the "[/quote]" part of each quote, or things get muddled.
I routinely forget and so I routinely have to edit my message and put those back in.