I have created a gallery using the node gallery module, beta-3 and I have confirmed that a file is uploaded to "sites/default/files/node_gallery/".
That is however all that seems to happen. There are no files in "sites/default/files/styles/node_gallery_display" or "sites/default/files/styles/node_gallery_thumbnail", which I think there should have been. I can see in my access logs that the server attempts to find files in those directories. Whatever the issue may be, I cannot see any images in my gallery.
I have been using latest stable views module, and drupal 7.15, but I will do some more testing after I get some sleep.