Replying to The ability to Edit a thread once created

this would be really useful for sale threads.   i keep having to make a new thread with new things im selling and its just a hassle.
If i could just add a few pictures/comments into the OP portion of the thread it would be easier.
I could just add them as a comment i know, but a lot of people wont read down to the bottom of a sale thread if they dont see anything they want in the OP

thoughts?
is this even possible?