Suggestions

[Barubary]

Or if you simply write _icon instead of -icon?

Whoops, it should have been _icon, but the idea is the same nonetheless.

I don't like the [sheet]-tag idea. What about the people who upload
their sheets on imageshack or another filehoster which manipulates
name and adress?
[...]
Is there really somebody who is too lazy to type ins some additional
tags?

I can understand these arguments against it, but it's just a suggestion ;]
If possible, maybe something like

Code:

[SHEET="http://www.site.com/dir/sheet.png" ICON="http://www.site2.com/dir2/sheeticon.gif"]title[/SHEET]

would solve the first problem.