You can't add a frame prior to frame #1, but you can add a frame after #1, and then move it up.
Click frame 1 and either insert an image (CTRL + I) or insert a frame. You can then move this up by clicking CTRL + U. You can't click CTRL + U immediately after inserting a frame - you have to select the frame first. Minor bug!
Not sure what you mean in your second part of the question. You can duplicate a frame, which will copy across its dimensions, and then move that to the top.