Can you post up what one of these skydrive iframe links looks like? You should be able to cut the actual link out from the middle of the [font=courier new,courier,monospace]<iframe src="..."></iframe>[/font] crap, which is probably a link to a web-page (not an image), which you can then open to find the actual image link.

[font=courier new,courier,monospace]iframe[/font]s are a HTML feature that allows you to embed a HTML page inside a HTML page. Most forums don't allow people to post raw HTML code (especially tags like iframe), because it allows posters to "hack" the forum layout for other readers.

Regarding YouTube, you can just paste the link to the video and the forum software automatically wraps you link in a [font=courier new,courier,monospace][ media ][/font] bbcode tag. e.g.
Test

Looks like:
Test
[media][/media]