It is maybe good to say that, in order of the workaround by @lafranglaise to work you have to temporarily deactivate the NextGen plugins, then you can upload your slides to the Slideshow gallery, if everything is ok, you should be able too see the thumbnail of the slides you add to your gallery. Then you can do the workaround and insert the [YOURSHORTCODE] in your post editor. It will work i am using wordpress 3.7.1 and Slideshow gallery Version 1.2.3.2
Thanks a lot LaFranglaise!! The workaround really works! Apparently NextGen conflicts also with other gallery image plugins, if we deactivate NextGen those plugins also work.
Hi! Did you get it working in your page http://willisgreenhouse.com/image-gallery/? or are you using other plugin?