Hmm strange thing, I just tested it, no problems.
it looks like you are in the media view, but you are in the category view. The available roles should be "no attribute", "downloadable", "product image".
What exactly do you mean with "replace". The available commands are for Image Action: None, upload, replace, replace thumb, create thumb.
Replace can also mean that you use "Attach new Image" and then you just edit all the time the same image. On the other hand the current file should never change. Hmmm