[Plugin: NextGEN Gallery] Can I set NextGen gallery to NOT resize my images?

I do not want NextGen to resize my images. I have landscape and portrait in the same gallery and I want my landscape images to be 800px wide but I want my portraits to be 600px high (not 800px, which is what it is resizing to. I am uploading the images in the sizes I want.
Any help is appreciated.

http://wordpress.org/extend/plugins/nextgen-gallery/