Do not Bump - On the chans threads (or breads) will age with no one posting in them, and eventually "fall off the board". When someone posts a reply in a thread they "bump" the thread. Pushing it back to the top of the page - thus helping the thread stay alive for more people to see and respond to. If it is a topic such as Bronies for example, you may feel compelled to reply and voice your opinion but do not wish to aid the thread then you would use the do not bump option.
The spoiler images one is simpler … Rather than displaying a thumbnail image of any image you post it will post a spoiler images icon and then if someone wants to see it they have to click through to see the pic.
WWG1WGA