Batch-resize in a fixed size

It would be nice that you could batch lots of pictures at once (of one or more different extensions) that then always fit in a given fixed size.

Let's say you want all you pictures in an 400x400 format but want to keep the proportion of you pictures.

Example:

I have 3 pictures with the following sizes:

- 900x1850
- 1240x452
- 350x790

The batch will pick up these files and always size the highest value (pixels) to the requisted fixed value you give in (like the 400x400 I pruposed) and keep them in proportion.
This way you will get whitespace arround the picture, and that's what we want.
Maybe it's nice to add an extra feature what the whitespace colour will become.

Example pictures:

[img]http://files.zilvex.com/PD_amscon_full.png[/img]
[img]http://files.zilvex.com/BK_383809_full.png[/img]

The first one had it's original picture in a higher value in the height of the picture.
The second on had it's original picture in a higher value in the width of the picture.

What I mean here is that the batch will identify by itself how to fit the picture you want in the box (like the 400x400 example).

Please respond because I'm not sure if I explain it right :-P