There's been some questions lately (mainly in the chat room) as to why people are unable to attach images to their posts. This is because there is no need to attach images to a post, so those file extensions have been disabled. Attachments are for files that cannot be embedded in the post, or have some specific reason they should be attached.
A forum post is similar to a blog post, or any other type of online article. The images are typically embedded in the page and are a viewable part of the content, similar to a book or a newspaper. Formatting like this makes it easier for the reader to stay focused on what he or she is reading, and not be distracted by having to click links and wait for images and/or bloated image hosting websites to load, and then hit the back button or close the extra tab or window to go back to what they were reading, hopefully not losing their place.
Below are some threads that explain how to properly add images to a post.
http://www.formicult...-photos/?p=7462
http://www.formicult...e-walk-through/
