choose original file for style?

Is there any way to force the Nivo Slider to use the original image instead of a styled, processed one? I have a JPG file that really looks quite nice until the system processes it. In the browser on my local machine, it's crisp. After uploading into the Nivo Slider, you can see the JPEG artifact along the contrast edges in the picture. While I prefer the creation of other style formats for many of my uploaded images, I would really prefer it if the Nivo Slider simply used the images I uploaded, without re-saving them upon upload. Is this possible? If not, consider this a feature request.