Image Help needed - should I rotate or what for mobile?

Hi all,

I am trying to create a simple page that displays one image on Mobile phones.

This image is landscape and roughly: width="600" height="240"

If I add an image tag like:

<img src="mypic.jpg" width="600" height="241" alt=""/>

portrait view...

it shows up too wide in portrait view - so you have to scroll left and right to see all of it. (not that great)

landscape view...

if you rotate the phone to landscape - it is just about full screen in landscape view. This is basically what I want.

Also it's upright in both views.

I am wondering if I can can set it up to start as already rotated in portrait mode which should encourage people to try to rotate their phone to see the better view.

I tried transform: rotate(90deg) but couldn't get it to show correctly (odd size - not left alight etc.)

Is there a good way to set this up?