Image change

Hi all,

I have a code question for you. I am lost with the answer so I hope someone can direct me.

Basically I have a wordpress site under development and I have created two custom image sizes within my functions file.

I am calling these images and a row of thumbnails and then above them is a larger box which I need a larger version of the thumbnail to show once the thumbnail is clicked.

I have this working at the moment by forcing a hard crop and changing the file names by the size WordPress adds to the end of the image name:-

$('#thumbs img').live('click', function(){
		$('#largeImage').attr('src',$(this).attr('src').replace('46x57','199x319'));
		$('#largeImageWindow').attr('src',$(this).attr('src').replace('46x57','398x500'));
 $('#description').html($(this).attr('alt'));
});

However I don’t want the image to be cropped! thus the height of the image is changeable when wordpress saves it.

How can I get the function to work with variable height images?

Thank you kind people,