Yup - when you are looking at the post (not editing the post) there is a set of links just above and to the right that starts with Thread Tools. There is a drop down menu with an option for Edit Thread. This will take you into a set of edit tools that are quite different from what you see with the Edit button at the lower left. One of the options in the Thread Tools dialogue is to edit the title.
Correct - it only gets bumped when a new post shows up. If you want to add an image to a thread and bump it you should edit the title to reflect additional media and then add a note at the bottom of the thread describing the additional content.
There is an issue with Uploading Photos (attachjments). I am not sure what the problem is, and I am looking into it. You can still try to Create your Threads and Upload your Photos, but it is hanging up during the Upload.