so, it's all about the tags. you can highlight stuff in the full editor and click IMG or YOUTUBE, or just do tags manually.
if you have a link to an image, like go to google, find an image (moving gif or static jpg/bmp/png), right click it and click "Copy Link Address" that would be an IMG url.
the layout is [IMG], then you insert your url, then you finish with the [] tags, but you put /IMG inside.
the / is kind of like End Tag Here.
same for YouTube/SoundCloud. YouTube is a little funky where anything that follows a ? is data that messes up the tags, so erase everything after a second question mark.
so if you were doing a YouTube link, this wouldn't work -
http://www.youtube.com/watch?v=uUmNmpGn ... BMq0hiff9wbut this would -
http://www.youtube.com/watch?v=uUmNmpGnKp4like so -
[youtube]http://www.youtube.com/watch?v=uUmNmpGnKp4&list=RD02BBMq0hiff9w[/youtube]
[youtube]http://www.youtube.com/watch?v=uUmNmpGnKp4[/youtube]
i put the YOUTUBE then /YOUTUBE tag around each of those url's in the [ ] brackets.