Some of you might already know this, but here is something I discovered last week. You can delete the ads shown on top of the images posted in threads.
When you copy and paste an image into a thread from another website, look at the bottom right hand corner of that image. You might see this:
Click on the "KIOSKED Ads" and then "Delete" on your keyboard. The ad should not show up after clicking "Submit." Try it next time.