Images getting chopped up

Thanks in advance. We bought Wunderslider (and Wunderslider Gallery) to show galleries of old images when WP-Supersized proved incapable of working well on mobile devices. Basically, we need to post LARGE numbers of images and resize them, because the originals are very small. Wunderslider is doing OK for the main gallery, which has over a hundred images, because they are all basically the same sizes.

But the second gallery has lots of odd sized images and they are being cut off on the bottom. Here is the link:

Gallery 2

Here is the code I used:

[gallery type=”slideshow” container_width=”80%” container_height=”600px” link=”none” ids=”674,675,676,677,678,679,680,681,682,688,687,686,685,684,683,689,690,691,692,693,694,695″]

What I would like to happen is to set it so that all images are displayed as 600 pixels tall, and the width would be proportional. I am a WYSIWYG designer, and I have no idea how to do that.

Thank for any help you can give!