Suggestions

[Virt]

Would it be possible to give the [img] tag some optional parameters that allow you to choose the image's size? That way people don't have to resize images manually if they're too big (or small, I guess).

You wouldn't even need to define width and height, you could just have a single width parameter and the height resizes accordingly (which would make it easier to keep the same proportion).

or a [thumb] tag, similar to facepunch