On latest Safari 3.2, the thumbnails are usually squished horizontally and overlapping closely. Very occasionally, they will render correctly as square thumbnails in a row. But then a refresh will break it again.
Since I can't upload a screenshot, I'll try to illustrate the problem in the glorious fidelity of ASCII!
Instead of a proper row of square thumbnails with space between like this:
[ ] [ ] [ ] [ ] [ ]
The thumbnails look all squished and overlapped like this:
The entire thumbnails are there but are highly condensed horizontally within their space.
Then if you mouse over them, they partially pop open but still overlap something like:
[ [ [ [ [ ]
The images are then slightly less squished horizontally but still overlapped.
This has been happening for all of the beta versions tested of NextGen 1.0 b in various versions of WP 2.7b. I prefer the thumbnails set to square (no landscapes or portraits), but have tried messing with all of the Thumbnail settings and the problem persists.
I have a rough staging site to try it out on at: http://staging.srwestend.com/nggallery/page-119/album-2/gallery-1/