To attach an image properly, upload it onto Imgur. Then take the image url (the one that ends with “.png”, or whichever other filetype you’re using), and put that in between image tags, like this:
[img]i.imgur.com/example.png[/img]
Once you do that, hit preview and it should show your image. Click it to zoom in without any blurring, and ctrl+click to zoom back out.