Advanced use of image-styles in a fixed-size DIV.

Hi all,

I'm dealing with a situation and I'm not quite sure what's the best solution. I'm having a site with a fixed size div: 530px X 340px (WxH).
In that box the client should be able to upload pic's that are resized down and cropped. I'm using the drupal.org/project/imagefield_crop module to let the client crop the proper part of the image.

To make things difficult, if a Portrait image is used the height should be max 340px, and may use a shorter width then 530px. (Let's say 340px X 200) would be OK.

What strategy would you recommend? Too make things clear, i've attached a picture of my situation.

Example of situation