Best option is to use the 'Advanced Options' of the views slideshow module itself.
Steps:
Create directory called json2 in sites/all/libraries and download https://raw.github.com/douglascrockford/JSON-js/master/json2.js and upload it in this folder.
Under jQuery Cycle Custom Options in advance options set add the following 1 by 1,
height: auto width: auto containerResize: 0 slideResize: 0 fit: 1