I am no longer able to edit the original post on the thread "Cataloguing Cetacean Exhibits." I am logged in and able to edit other posts, but the edit button is no longer present on the original post. I was able to edit this post just a few hours ago, though.
I have a feeling that one can only edit a post within 48 hours of originally uploading it, unless one is a moderator - if so, the post has ticked over that point in the last few hours.
Though I think you can edit the titles of pictures indefinitely. I have just checked some pictures I uploaded 10 months ago and I am able to edit the titles.
1) you can edit your own posts within a 48 hour period. 2) you can edit your own photo titles whenever you want (in the past you couldn't). 3) you cannot edit your thread titles (I think - that may have changed as well; someone could check that if they want).